C String Exercises

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Course:	CS107: C++ Programming
Book:	C String Exercises

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Date:	Friday, 4 April 2025, 12:34 AM

Description

Complete these exercises to test your understanding of string arrays.

C String Exercises
C String: Solutions

C String Exercises

Exercise 1

Write a program in C to input a string and print it.

Test Data:
Input the string: Welcome, w3resource

Expected Output:

The string you entered is: Welcome, w3resource

Exercise 2

Write a program in C to find the length of a string without using library function.

Test Data:
Input the string: w3resource.com

Expected Output:

Length of the string is: 15

Exercise 3

Write a program in C to separate the individual characters from a string.

Test Data:
Input the string: w3resource.com

Expected Output:

The characters of the string are: 
w  3  r  e  s  o  u  r  c  e  .  c  o  m

Exercise 4

Write a program in C to print individual characters of string in reverse order.

Test Data:
Input the string: w3resource.com

Expected Output:

The characters of the string in reverse are:
m  o  c  .  e  c  r  u  o  s  e  r  3  w

Exercise 5

Write a program in C to count the total number of words in a string.

Test Data:
Input the string: This is w3resource.com

Expected Output:

Total number of words in the string is: 3

Exercise 6

Write a program in C to compare two strings without using string library functions.

Test Data:
Check the length of two strings:
--------------------------------
Input the 1st string: aabbcc
Input the 2nd string: abcdef
String1: aabbcc
String2: abcdef

Expected Output:

Strings are not equal.

Check the length of two strings:
--------------------------------
Input the 1st string: aabbcc
Input the 2nd string: aabbcc
String1: aabbcc
String2: aabbcc

Expected Output:

Strings are equal.

Exercise 7

Write a program in C to count total number of alphabets, digits and special characters in a string.

Test Data:
Input the string: Welcome to w3resource.com

Expected Output:

Number of Alphabets in the string is: 21 
Number of Digits in the string is: 1 
Number of Special characters in the string is: 4

Exercise 8

Write a program in C to copy one string to another string.

Test Data:
Input the string: This is a string to be copied.

Expected Output:

The First string is: This is a string to be copied.
The Second string is: This is a string to be copied. 
Number of characters copied: 31

Exercise 9

Write a program in C to count total number of vowel or consonant in a string.

Test Data:
Input the string: Welcome to w3resource.com

Expected Output:

The total number of vowel in the string is: 9 
The total number of consonant in the string is: 12

Exercise 10

Write a program in C to find maximum occurring character in a string.

Test Data:
Input the string: Welcome to w3resource.com.

Expected Output:

The Highest frequency of character 'e' 
appears number of times: 4

Exercise 11

Write a C program to sort a string array in ascending order.

Test Data:
Input the string: w3resource

Expected Output:

After sorting the string appears like: 
3ceeorrsuw

Exercise 12

Write a program in C to read a string through keyboard and sort it using bubble sort.

Test Data:
Input number of strings :3
Input string 3:
zero
one
two

Expected Output:

The strings appears after sorting: 
one 
two 
zero

Exercise 13

Write a program in C to extract a substring from a given string.

Test Data:
Input the string: this is test string
Input the position to start extraction: 9
Input the length of substring: 4

Expected Output:

The substring retrieve from the string is: "test"

Exercise 14

Write a C program to check whether a given substring is present in the given string.

Test Data:
Input the string: This is a test string.
Input the substring to be search: search

Expected Output:

The substring is not exists in the string.

Exercise 15

Write a program in C to read a sentence and replace lowercase characters by uppercase and vice-versa.

Test Data:
Input the string: This Is A Test String.

Expected Output:

The given sentence is: This Is A Test String.
After Case changed the string  is: tHIS iS a tEST sTRING.

Exercise 16

Write a program in C to find the number of times a given word 'the' appears in the given string.

Test Data:
Input the string: The string where the word the present more than once.

Expected Output:

The frequency of the word 'the' is: 3

Exercise 17

Write a program in C to remove characters in String Except Alphabets.

Test Data:
Input the string: w3resource.com

Expected Output:

After removing the Output String: wresourcecom

Exercise 18

Write a program in C to Find the Frequency of Characters.

Test Data:
Input the string: This is a test string
Input the character to find frequency: i

Expected Output:

The frequency of 'i' is: 3

Exercise 19

Write a program in C to Concatenate Two Strings Manually.
Test Data :
Input the first string: this is string one
Input the second string: this is string two

Expected Output:

After concatenation the string is: 
this is string one this is string two

Exercise 20

Write a program in C to find the largest and smallest word in a string.

Test Data:
Input the string: It is a string with smallest and largest word.

Expected Output:

The largest word is 'smallest'
and the smallest word is 'a' 
in the string: 'It is a string with smallest and largest word.'.

Exercise 21

Write a program in C to convert a string to uppercase.

Test Data:
Input a string in lowercase: the quick brown fox jumps over the lazy dog

Expected Output:

Here is the above string in UPPERCASE :                                
 THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG.

Exercise 22

Write a program in C to convert a string to lowercase.

Test Data:
Input a string in UPPERCASE: THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG.

Expected Output:

Here is the above string in lowercase:                              
the quick brown fox jumps over the lazy dog.

Exercise 23

Write a program in C to check whether a character is Hexadecimal Digit or not.
Test Data:
Input a character: 7

Expected Output:

The entered character is a hexadecimal digit.

Exercise 24

Write a program in C to check whether a letter is uppercase or not.
Test Data:
Input a character: p

Expected Output:

The entered letter is not an UPPERCASE letter.

Exercise 25

Write a program in C to replace the spaces of a string with a specific character.

Test Data:
Input a string: Be glad to see the back of Input replace character: *

Expected Output:

After replacing the space with  * the new string is:                 
Be*glad*to*see*the*back*of*

Exercise 26

Write a program in C to count the number of punctuation characters exists in a string.

Test Data:
Input a string: The quick brown fox, jumps over the, lazy dog.

Expected Output:

The punctuation characters exists in the string is: 3

Exercise 27

Write a program in C to print only the string before new line character.

Note: isprint() will only print line one, because the newline character is not printable.

Expected Output:

The quick brown fox

Exercise 28

Write a program in C to check whether a letter is lowercase or not.

Test Data:
Input a character: w

Expected Output:

The entered letter is a lowercase letter.

Exercise 29

Write a program in C to read a file and remove the spaces between two words of its content.

Expected Output:

The content of the file is:                                           
The quick brown fox jumps over the lazy dog                            
After removing the spaces the content is:                             
Thequickbrownfoxjumpsoverthelazydog

Exercise 30

Write a program in C to check whether a character is digit or not.

Test Data:
Input a character: 8

Expected Output:

The entered character is a digit.

Exercise 31

Write a program in C to split string by space into words.

Test Data:
Input a string: this is a test string

Expected Output:

Strings or words after split by space are : 

this
is 
a 
test 
string .

Exercise 32

Write a C programming to find the repeated character in a given string.

Test Data:
Input a string: w3resource

Expected Output:

Input a string: The first repetitive character in w3resource is: r

Exercise 33

Write a C programming to count of each character in a given string.

Test Data:
Input a string: w3resource

Expected Output:

Enter a str1ing: The count of each character in the string w3resource is 
w	1
3	1
r	2
e	2
s	1
o	1
u	1
c	1

Exercise 34

Write a C programming to convert vowels into upper case character in a given string.

Test Data:
Input a string: w3resource

Expected Output:

Input a sentence: The original string:
w3resource
After converting vowels into upper case the sentence becomes:
w3rEsOUrcE

Source: W3resource, https://www.w3resource.com/c-programming-exercises/string/index.php
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License.

C String: Solutions

Exercise 1

Write a program in C to input a string and print it.

C Programming: Accept a string from keyboard

Sample Solution:

C Code:

#include <stdio.h>  
#include <stdlib.h>  
  
void main()
{
    char str[50];
    
    printf("\n\nAccept a string from keyboard:\n");
   
    printf("-----------------------------------\n");     
    printf("Input the string: ");
    fgets(str, sizeof str, stdin);
    printf("The string you entered is: %s\n", str);
}

Sample Output:

Accept a string from keyboard:

-----------------------------------
Input the string: Welcome, w3resource
The string you entered is: Welcome, w3resource

Flowchart:

Flowchart: nAccept a string from keyboard.

Exercise 2

Write a program in C to find the length of a string without using library function.

C Programming: Find the length of a string

Sample Solution:

C Code:

#include <stdio.h>
#include <stdlib.h>

void main()
{
    char str[100]; /* Declares a string of size 100 */
    int l= 0;
    
      
printf("\n\nFind the length of a string:\n");
       printf("---------------------------------\n");     
       printf("Input the string: ");
      
fgets(str, sizeof str, stdin);
    while(str[l]!='\0')
    {
        l++;
    }
    printf("Length of the string is: %d\n\n", l-1);
}

Sample Output:

Find the length of a string:
---------------------------------
Input the string: w3resource.com
Length of the string is: 15

Flowchart:

Exercise 3

Write a program in C to separate the individual characters from a string.

C Programming: Separate the individual characters from a string

Sample Solution:

C Code:

#include <stdio.h>
#include <stdlib.h>


void main()
{
    char str[100]; /* Declares a string of size 100 */
    int l= 0;
    
      
printf("\n\nSeparate the individual characters from a string:\n");
       printf("------------------------------------------------------\n");     
       printf("Input the
string : ");
       fgets(str, sizeof str, stdin);
       printf("The characters of the string are: \n");
    while(str[l]!='\0')
    {
      
printf("%c  ", str[l]);
       l++;
    }
    printf("\n");
}

Sample Output:

Separate the individual characters from a string:
------------------------------------------------------
Input the string: w3resource.com
The characters of the string are:
w 3 r e s o u r c e . c o m

Flowchart:

Exercise 4

Write a program in C to print individual characters of string in reverse order.

C Programming: Print individual characters of string in reverse order

Sample Solution:

C Code:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

void main()
{
    char str[100]; /* Declares a string of size 100 */
    int l,i;
  
 
       printf("\n\nPrint individual characters of string in reverse order:\n");
       printf("------------------------------------------------------\n");     
      
printf("Input the string: ");
       fgets(str, sizeof str, stdin);
       l=strlen(str);
       printf("The characters of the string in reverse are: \n");
      
for(i=l;i>=0;i--)
        {
          printf("%c  ", str[i]);
        }
    printf("\n");
}

The program can also be written as below:


#include <stdio.h>
#include <string.h>
#include <stdlib.h>

void main()
{
    char str[100]; /* Declares a string of size 100 */
   
int l=0;
    
       printf("\n\nPrint individual characters of string in reverse order:\n");
       printf("------------------------------------------------------\n");
    
       printf("Input the string: ");
       fgets(str, sizeof str, stdin);
       l=strlen(str);
       printf("The
characters of the string in reverse are: \n");
       for(str[l]='\0';l>=0;l--)
        {
          printf("%c  ", str[l]);
       
}
    printf("\n");
}

Sample Output:

Print individual characters of string in reverse order:
-----------------------------------------------------------
Input the string: w3resource.com
The characters of the string in reverse are:

m o c . e c r u o s e r 3 w

Flowchart :

Exercise 5

Write a program in C to count the total number of words in a string.

C Programming: Count the total number of words in a string

Sample Solution:

C Code:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define str_size 100 //Declare the maximum size of the string

void main()
{
    char str[str_size];
   
int i, wrd;
    
       printf("\n\nCount the total number of words in a string:\n");
       printf("------------------------------------------------------\n");    

       printf("Input the string: ");
       fgets(str, sizeof str, stdin);    
    
    i = 0;
    wrd = 1;

   
/* loop till end of string */
    while(str[i]!='\0')
    {
        /* check whether the current character is white space or new line or tab character*/
       
if(str[i]==' ' || str[i]=='\n' || str[i]=='\t')
        {
            wrd++;
        }

       
i++;
    }

    printf("Total number of words in the string is: %d\n", wrd-1);
}

Sample Output:

Count the total number of words in a string:
------------------------------------------------------
Input the string: This is w3resource.com
Total number of words in the string is: 3

Flowchart:

Exercise 6

Write a program in C to compare two strings without using string library functions.

Sample Solution:

C Code:

 // C program to compare the two strings
// without using strcmp() function
#include <stdio.h>
#define str_size 100 //Declare the maximum size of the string
int test(char* s1, char* s2)
{
        
int flag = 0;
         while (*s1 != '\0' || *s2 != '\0') {
                  if (*s1 == *s2) {
                           
s1++;
                            s2++;
                 
}
        else if ((*s1 == '\0' && *s2 != '\0')
                                    
|| (*s1 != '\0' && *s2 == '\0')
                                    
|| *s1 != *s2) {
                            flag = 1;
                           
break;
                  }
         }
  return flag;
}
int main(void)
{
char str1[str_size], str2[str_size];
  
int flg=0;
   printf("\nInput the 1st string: ");
   fgets(str1, sizeof str1, stdin);
   printf("Input the 2nd string: ");
   fgets(str2, sizeof str2, stdin);        
 
   printf("\nString1: %s", str1);
   printf("String2: %s", str2);
   flg = test(str1, str2);
    if(flg == 0)
   {
       printf("\nStrings are
equal.\n");
   }
   else if(flg == 1)
   {
      printf("\nStrings are not equal.");
   }
         return 0;
}

Sample Output:

Check the length of two strings:
--------------------------------
Input the 1st string: aabbcc
Input the 2nd string: abcdef

String1: aabbcc
String2: abcdef

Strings are not equal.

Sample Output:

Check the length of two strings:
--------------------------------
Input the 1st string: aabbcc
Input the 2nd string: aabbcc

String1: aabbcc
String2: aabbcc

Strings are equal.

Flowchart:

Exercise 7

Write a program in C to count total number of alphabets, digits and special characters in a string.

C Programming: Count total number of alphabets, digits and special characters

Sample Solution:

C Code:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>


#define str_size 100 //Declare the maximum size of the string

void main()
{
    char str[str_size];
   
    int alp, digit, splch, i;
    alp = digit = splch = i = 0;


       printf("\n\nCount total number of alphabets, digits and special characters :\n");
      
    printf("--------------------------------------------------------------------\n");     
       printf("Input the string: ");
       fgets(str, sizeof str, stdin);   
    

     /* Checks each character of string*/

    while(str[i]!='\0')
    {
        if((str[i]>='a' && str[i]<='z') || (str[i]>='A'
    && str[i]<='Z'))
        {
            alp++;
        }
       
    else if(str[i]>='0' && str[i]<='9')
        {
            digit++;
        }
       
    else
        {
            splch++;
        }

        i++;
   
    }

    printf("Number of Alphabets in the string is: %d\n", alp);
    printf("Number of Digits in the string is: %d\n", digit);
    printf("Number of Special characters in the string is:
    %d\n\n", splch);
}

Sample Output:

Count total number of alphabets, digits and special characters:
--------------------------------------------------------------------
Input the string: Welcome to w3resource.com
Number of Alphabets in the string is: 21
Number of Digits in the string is: 1
Number of Special characters in the string is: 4

Flowchart:

Exercise 8

Write a program in C to copy one string to another string.

C Programming: Copy one string into another string

Sample Solution:

C Code:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>


void main()
{
    char str1[100], str2[100];
    int  i;

      
    printf("\n\nCopy one string into another string:\n");
       printf("-----------------------------------------\n");     
       printf("Input the string: ");
      
    fgets(str1, sizeof str1, stdin);
       
    /* Copies string1 to string2 character by character */
    i=0;
    while(str1[i]!='\0')
    {
       
    str2[i] = str1[i];
        i++;
    }

    //Makes sure that the string is NULL terminated
    str2[i] = '\0';

    printf("\nThe First
    string is : %s\n", str1);
    printf("The Second string is: %s\n", str2);
    printf("Number of characters copied: %d\n\n", i);
}

Sample Output:

Copy one string into another string:
-----------------------------------------
Input the string: This is a string to be copied.

The First string is: This is a string to be copied.

The Second string is: This is a string to be copied.

Number of characters copied: 31

Flowchart:

Exercise 9

Write a program in C to count total number of vowel or consonant in a string.

C Programming: Count total number of vowel or consonant

Sample Solution:

C Code:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define str_size 100 //Declare the maximum size of the string

void main()
{
    char str[str_size];
   
    int i, len, vowel, cons;
    
       printf("\n\nCount total number of vowel or consonant:\n");
       printf("----------------------------------------------\n");
        
       printf("Input the string: ");
       fgets(str, sizeof str, stdin);    

    vowel = 0;
    cons =
    0;
    len = strlen(str);

    for(i=0; i<len; i++)
    {

        if(str[i] =='a' || str[i]=='e' || str[i]=='i' || str[i]=='o' || str[i]=='u' ||
    str[i]=='A' || str[i]=='E' || str[i]=='I' || str[i]=='O' || str[i]=='U')
        {
            vowel++;
        }
       
    else if((str[i]>='a' && str[i]<='z') || (str[i]>='A' && str[i]<='Z'))
        {
            cons++;
       
    }
    }
    printf("\nThe total number of vowel in the string is: %d\n", vowel);
    printf("The total number of consonant in the string is: %d\n\n", cons);
}

Sample Output:

Count total number of vowel or consonant:
----------------------------------------------
Input the string : Welcome to w3resource.com

The total number of vowel in the string is: 9
The total number of consonant in the string is: 12

Flowchart:

Exercise 10

Write a program in C to find maximum occurring character in a string.

C Programming: Find maximum occurring character in a string

Sample Solution:

C Code:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define str_size 100 //Declare the maximum size of the string
#define chr_no 255 //Maximum number of characters to be
    allowed

void main()
{
    char str[str_size];
    int ch_fre[chr_no];
    int i = 0, max;
    int ascii;
    
      
    printf("\n\nFind maximum occurring character in a string:\n");
       printf("--------------------------------------------------\n");     
       printf("Input the string
    : ");
       fgets(str, sizeof str, stdin);


    for(i=0; i<chr_no; i++)  //Set frequency of all characters to 0
    {
       
    ch_fre[i] = 0;
    }


    /* Read for frequency of each characters */
    i=0;
    while(str[i] != '\0')
    {
       
    ascii = (int)str[i];
        ch_fre[ascii] += 1;

        i++;
    }

    max = 0;
    for(i=0; i<chr_no; i++)
   
    {
        if(i!=32)
        {
        if(ch_fre[i] > ch_fre[max])
           
    max = i;
        }
    }    
    printf("The Highest frequency of character '%c' appears number of times: %d \n\n", max, ch_fre[max]);
}

Sample Output:

Find maximum occurring character in a string:
--------------------------------------------------
Input the string: Welcome to w3resource
The Highest frequency of character 'e' appears number of times: 4

Flowchart:

Exercise 11

Write a C program to sort a string array in ascending order.

C Programming: Sort a string array in ascending order

Sample Solution:

C Code:

#include <stdio.h>
#include <string.h>
void
    main()
{
  char str[100],ch;
  int i,j,l;
  
       printf("\n\nSort a string array in ascending order:\n");
       printf("--------------------------------------------\n");
     
       printf("Input the string : ");
       fgets(str, sizeof str, stdin);
  l=strlen(str);
  /* sorting process */
  for(i=1;i<l;i++)
   
    for(j=0;j<l-i;j++)
    if(str[j]>str[j+1])
    {
      ch=str[j];
      str[j] = str[j+1];
      str[j+1]=ch;
    }
  
    printf("After sorting the string appears like: \n");
   printf("%s\n\n",str);
  }

Sample Output:

Sort a string array in ascending order:
--------------------------------------------
Input the string: w3resource
After sorting the string appears like:

3ceeorrsuw

Flowchart :

Exercise 12

Write a program in C to read a string through keyboard and sort it using bubble sort.

C Programming: Sorts the strings of an array using bubble sort

Sample Solution:

C Code:

#include <stdio.h>
#include
    <string.h>
void main()
{
  char name[25][50],temp[25];
  int n,i,j;
  
       printf("\n\nSorts the strings of an array using bubble sort :\n");
      
    printf("-----------------------------------------------------\n");  
  
 
  printf("Input number of strings :");
  scanf("%d",&n);

printf("Input string %d :\n",n);
  for(i=0;i<=n;i++)
 
    {
       
       fgets(name[i], sizeof name, stdin);
  }
     /*Logic Bubble Sort*/

     for(i=1;i<=n;i++)
  
     for(j=0;j<=n-i;j++)
      if(strcmp(name[j],name[j+1])>0)
      { 
            strcpy(temp,name[j]);
       
    strcpy(name[j],name[j+1]);
        strcpy(name[j+1],temp);
      }
   printf("The strings appears after sorting:\n");
          for(i=0;i<=n;i++)
  
          printf("%s\n",name[i]);
 
}

Sample Output:

Sorts the strings of an array using bubble sort:
-----------------------------------------------------
Input number of strings: 3
Input string 3:
zero
one
two
The strings appears after sorting:

one

two

zero

Flowchart:

Exercise 13

Write a program in C to extract a substring from a given string.

C Programming: Extract a substring from a given string

Sample Solution:

C Code:

#include <stdio.h>
void main() 
{
  
    char str[100], sstr[100];
   int pos, l, c = 0;
   
       printf("\n\nExtract a substring from a given string:\n");
       printf("--------------------------------------------\n");
     
 
       printf("Input the string: ");
       fgets(str, sizeof str, stdin);
 
   printf("Input the position to start extraction:");
  
    scanf("%d", &pos);
   
   printf("Input the length of substring:");
   scanf("%d", &l);
 
   while (c < l) 
   {
      sstr[c] = str[pos+c-1];
     
    c++;
   }
   sstr[c] = '\0';
 
   printf("The substring retrieve from the string is: \" %s\ "\n\n", sstr);
 
}

Sample Output:

Extract a substring from a given string:
--------------------------------------------
Input the string: This is test string
Input the position to start extraction: 9
Input the length of substring: 4
The substring retrieve from the string is: " test "

Flowchart:

Exercise 14

Write a C program to check whether a given substring is present in the given string.

C Programming: Check whether a given substring is present in the given string

Sample Solution:

C Code:

#include <stdio.h>
        
void main()
{
    char str[80],search[20];    
    int c1=0,c2=0,i,j,flg;
    
       printf("\n\nCheck whether a given  substring
        is present in the given string :\n");
       printf("-------------------------------------------------------------------\n");    
    

       
        printf("Input the string: ");
        fgets(str, sizeof str, stdin);

    printf("Input the substring to be search: ");
    fgets(search, sizeof search, stdin);

  
         while (str[c1]!='\0')
        c1++;
                c1--;

    while (search[c2]!='\0')
       
        c2++;
        
                c2--;


    for(i=0;i<=c1-c2;i++)
    { 
        for(j=i;j<i+c2;j++)
  
             {
            flg=1;
            if (str[j]!=search[j-i])
            {
  
                     flg=0;
               break;
            }
       
        }
        
        if (flg==1)
            break;
    }
    if (flg==1)
        printf("The substring exists
        in the string.\n\n");
    else
        printf("The substring is not exists in the string. \n\n");
}

Sample Output:

Check whether a given substring is present in the given string:
-------------------------------------------------------------------
Input the string: This is a test string.
Input the substring to be search: search
The substring is not exists in the string.

Flowchart :

Exercise 15

Write a program in C to read a sentence and replace lowercase characters by uppercase and vice-versa.

C Programming: Replace lowercase characters by uppercase and vice-versa

Sample Solution:

C Code:

#include <stdio.h>
        
#include <string.h>
#include <ctype.h>

void main()
{
  char str[100];
  int ctr, ch, i;

       printf("\n\nReplace lowercase characters by uppercase and vice-versa:\n");
       printf("--------------------------------------------------------------\n");    

       printf("Input the string: ");
      
        fgets(str, sizeof str, stdin);  

  i=strlen(str);

  ctr = i; /*shows the number of chars accepted in a sentence*/

  printf("\nThe given sentence is: %s",str);

  printf("After Case
        changed the string  is: ");
  for(i=0; i < ctr; i++)
  {
    ch = islower(str[i]) ? toupper(str[i]) : tolower(str[i]);
    putchar(ch);
   }
   printf("\n\n");

}

Sample Output:

Replace lowercase characters by uppercase and vice-versa:
--------------------------------------------------------------
Input the string: This Is A Test String

The given sentence is: This Is A Test String
After Case changed the string is: tHIS iS a tEST sTRING

Flowchart :

Exercise 16

Write a program in C to find the number of times a given word 'the' appears in the given string.

C Programming: Find the number of times the word 'the' in any combination appears

Sample Solution:

C Code:

#include
    <stdio.h>
#include <string.h>
void main()
{
    int ctr=0,i,freq=0;
        int t,h,e,spc;
    char str[100];
    
    
      
    printf("\n\nFind the number of times the word 'the ' in any combination appears:\n");
       printf("----------------------------------------------------------------------\n");    

  
     printf("Input the string: ");
    fgets(str,sizeof str,stdin);

        ctr=strlen(str);

    /*Counts the frequency of the word 'the' with a trailing space*/
  
     for(i=0;i<=ctr-3;i++)
    {
        t=(str[i]=='t'||str[i]=='T');
        h=(str[i+1]=='h'||str[i+1]=='H');
        e=(str[i+2]=='e'||str[i+2]=='E');
  
         spc=(str[i+3]==' '||str[i+3]=='\0');
        if ((t&&h&&e&&spc)==1)
           freq++;
    }
  
     printf("The frequency of the word \'the\' is: %d\n\n",freq);
}

Sample Output:

Find the number of times the word 'the ' in any combination appears:
----------------------------------------------------------------------
Input the string: The stering where the word the present more then onces.
The frequency of the word 'the' is: 3

Flowchart:

Exercise 17

Write a program in C to remove characters in String Except Alphabets.

C Programming: Remove characters in String Except Alphabets

Sample Solution:

C Code:

#include <stdio.h>
#include <string.h>
void
    main(){
    char str[150];
    int i,j;
    
       printf("\n\nRemove characters in String Except Alphabets:\n");
       printf("--------------------------------------------------\n");   
    

    printf("Input the string : ");
    fgets(str,sizeof str,stdin);    
    for(i=0; str[i]!='\0'; ++i)
    {
       
    while (!((str[i]>='a'&&str[i]<='z') || (str[i]>='A'&&str[i]<='Z' || str[i]=='\0')))
        {
            for(j=i;str[j]!='\0';++j)
           
    {
                str[j]=str[j+1];
            }
           
    str[j]='\0';
        }
    }
    printf("After removing the Output String: %s\n\n",str);
}

Sample Output:

Remove characters in String Except Alphabets :
--------------------------------------------------
Input the string: W3resource.com
After removing the Output String: Wresourcecom

Flowchart:

Exercise 18

Write a program in C to Find the Frequency of Characters.

C Programming: Find the Frequency of Characters

Sample Solution:

C Code:

#include <stdio.h>
void main(){
   char str[1000],choice;
  
    int i,ctr=0;
   
       printf("\n\nFind the Frequency of Characters:\n");
       printf("--------------------------------------\n");    
  
        
    printf("Input the string : ");
    fgets(str,sizeof str,stdin);
    
   printf("Input the character to find frequency: ");
   scanf("%c",&choice);
  
    for(i=0;str[i]!='\0';++i)
   {
       if(choice==str[i])
           ++ctr;
   }
   printf("The frequency of '%c' is: %d\n\n",
    choice, ctr);
}

Sample Output:

Find the Frequency of Characters:
--------------------------------------
Input the string: This is a test string
Input the character to find frequency: i
The frequency of 'i' is: 3

Flowchart:

Exercise 19

Write a program in C to Concatenate Two Strings Manually.

C Programming: Concatenate Two Strings Manually

Sample Solution:

C Code:

#include <stdio.h>
#include <string.h>
void main()
{
   
    char str1[100], str2[100], i, j,l,m,k;
    
       printf("\n\nConcatenate Two Strings Manually:\n");
       printf("-------------------------------------\n");   
    

    printf("Input the first string: ");
    fgets(str1,sizeof str1,stdin);
    printf("Input the second string: ");
    fgets(str2,sizeof str2,stdin);
   
    l=strlen(str1);
    m=strlen(str2);
    for(i=0; i<l-1; ++i);  /* value i contains reaches the end of string str1. */  
    str1[i]=' ';           
    /* add a space with string str1. */ 
    i++;                  /* value i increase by 1 for the blank space */ 

    for(j=0;
    j<m-1; ++j, ++i)
    {
        str1[i]=str2[j];
    }
     k=strlen(str1);   

    printf("After concatenation the string
    is: \n ");    
    for(i=0; i<k; ++i)    
    {
         printf("%c",str1[i]);
    }
printf("\n\n");
}

Sample Output:

Concatenate Two Strings Manually:
-------------------------------------
Input the first string: this is string one
Input the second string: this is string two
After concatenation the string is:
this is string one this is string two

Flowchart:

Flowchart: Concatenate Two Strings Manually

Exercise 20

Write a program in C to find the largest and smallest word in a string.

C Programming: Find the largest and smallest word in a string

Sample Solution:

C Code:

#include <stdio.h>
#include
    <string.h>
#include <ctype.h>

void main()
{
    char str[100], word[20], mx[20], mn[20], c;
    int i = 0, j = 0, flg = 0;
    
      
    printf("\n\nFind the largest and  smallest word in a string:\n");
       printf("-----------------------------------------------------\n");        
 
    printf("Input
    the string : ");
    i = 0;
    do
    {
        fflush(stdin);
        c = getchar();
       
    str[i++] = c;
 
    } while (c != '\n');
    str[i - 1] = '\0';
    for (i = 0; i < strlen(str); i++)
    {
        while (i <
    strlen(str) && !isspace(str[i]) && isalnum(str[i]))
        {
            word[j++] = str[i++];
       
    }
        if (j != 0)
        {
            word[j] = '\0';
           
    if (!flg)
            {
                flg = !flg;
               
    strcpy(mx, word);
                strcpy(mn, word);
            }
           
    if (strlen(word) > strlen(mx))
            {
                strcpy(mx, word);
           
    }
            if (strlen(word) < strlen(mn))
            {
               
    strcpy(mn, word);
            }
            j = 0;
        }
    }
   
    printf("The largest word is '%s' \nand the smallest word is '%s' \nin the string: '%s'.\n", mx, mn, str);
 }

Sample Output:

Find the largest and smallest word in a string:
-----------------------------------------------------
Input the string: It is a string with smallest and largest word.
The largest word is 'smallest'
and the smallest word is 'a'
in the string: 'It is a string with smallest and largest word'.

Flowchart:

Exercise 21

Write a program in C to convert a string to uppercase.

C Programming: Convert a string to uppercase

Sample Solution:

C Code:

#include<stdio.h>
#include<ctype.h>

int main()
{
  
     int ctr=0;
    char str_char;
    char str[100]; 
    
    printf("\n Convert a string to uppercase:\n");  
    printf("-----------------------------------");    
     
    printf("\n Input a string in lowercase: ");
    fgets(str, sizeof str, stdin);  
    printf(" Here is the above string in UPPERCASE:\n ");
    while (str[ctr])
  
     {
        str_char=str[ctr];
        putchar (toupper(str_char));
        ctr++;
    }
    printf("\n\n");
  
     return 0;
}

Sample Output:

Convert a string to uppercase:
-----------------------------------
Input a string in lowercase: the quick brown fox jumps over the lazy dog.
Here is the above string in UPPERCASE:
THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG.

Flowchart:

Exercise 22

Write a program in C to convert a string to lowercase.

C Programming: Convert a string to lowercase

Sample Solution:

C Code:

#include<stdio.h>
#include<ctype.h>

int main()
{
  
     int ctr=0;
    char str_char;
    char str[100]; 
    
    printf("\n Convert a string to lowercase:\n");  
    printf("----------------------------------");    
     
    printf("\n Input a string in UPPERCASE: ");
    fgets(str, sizeof str, stdin);  
    printf(" Here is the above string in lowercase:\n ");    
    while
    (str[ctr])
    {
        str_char=str[ctr];
        putchar (tolower(str_char));
        ctr++;
    }
  
     return 0;
}

Sample Output:

Convert a string to lowercase:
----------------------------------
Input a string in UPPERCASE: THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG.
Here is the above string in lowercase:
the quick brown fox jumps over the lazy dog.

Flowchart:

Exercise 23

Write a program in C to check whether a character is Hexadecimal Digit or not.

C Programming: Check whether a character is Hexadecimal Digit or not

Sample Solution:

C Code:

#include<stdio.h>
#include<ctype.h>


int
    main()
{
    char TestChar;
    printf("\n Check whether a character is Hexadecimal Digit or not:\n");  
    printf("-------------------------------------------------------\n");    
     
    printf(" Input a character: "); // Hexadecimal Digits are a-f, A-F or 0-9
    scanf( "%c", &TestChar );
    if( isxdigit(TestChar) )
        printf(
    " The entered character is a hexadecimal digit. \n" );
    else
        printf( " The entered character is not a hexadecimal digit. \n" );
    return 0;
}

Sample Output:

Check whether a character is Hexadecimal Digit or not:
-------------------------------------------------------
Input a character: 7
The entered character is a hexadecimal digit.

Flowchart:

Exercise 24

Write a program in C to check whether a letter is uppercase or not.

C Programming: Check whether a letter is uppercase or not

Sample Solution:

C Code:

#include<stdio.h>
#include<ctype.h>

int
    main()
{
    char TestChar;
    printf("\n Check whether a letter is uppercase or not:\n");  
    printf("------------------------------------------------\n");    
     
    printf(" Input a character: "); 
    scanf( "%c", &TestChar );
    if( isupper(TestChar) )
        printf( " The entered letter is an UPPERCASE
    letter. \n" );
    else
        printf( " The entered letter is not an UPPERCASE letter. \n" );
    return 0;
}

Sample Output:

Check whether a letter is uppercase or not:
------------------------------------------------
Input a character: p
The entered letter is not an UPPERCASE letter.

Flowchart :

Exercise 25

Write a program in C to replace the spaces of a string with a specific character.

C Programming: Replace the spaces of a string with a specific character

Sample Solution:

C Code:

#include<stdio.h>
#include<ctype.h>

int
    main()
{
    int new_char;
    char t;
    int ctr=0;
    char str[100]; 
    printf("\n Replace the spaces of a string with a specific character:\n"); 
    
    printf("-------------------------------------------------------------\n");      
    printf(" Input a string: ");
    fgets(str, sizeof str, stdin); 
   
    printf(" Input replace character: ");
    scanf("%c",&t);
    printf(" After replacing the space with  %c the new string is:\n",t);
    while (str[ctr])
    {
  
         new_char=str[ctr];
        if (isspace(new_char)) 
        new_char=t;
        putchar (new_char);
       
    ctr++;
    }
    printf("\n\n");
    return 0;
}

Sample Output:

Replace the spaces of a string with a specific character:
-------------------------------------------------------------
Input a string: Be glad to see the back of
Input replace character: *
After replacing the space with * the new string is:
Be*glad*to*see*the*back*of*

Flowchart:

Exercise 26

Write a program in C to count the number of punctuation characters exists in a string.

C Programming: Count the number of punctuation characters exists in a string

Sample Solution:

C Code:

#include<stdio.h>
#include<ctype.h>

int main()
        
{
    int ctr1=0;
    int ctr2=0;
    char str[100]; 
    printf("\n Count the number of punctuation characters exists in a string:\n");  
   
        printf("------------------------------------------------------------------\n");    
    printf(" Input a string: ");
    fgets(str, sizeof str, stdin);     
    while
        (str[ctr1])
        
    {
        if (ispunct(str[ctr1])) ctr2++;
        ctr1++;
    }
    printf (" The punctuation characters exists in the
        string is: %d\n\n", ctr2);
      return 0;
}

Sample Output:

Count the number of punctuation characters exists in a string:
------------------------------------------------------------------
Input a string: The quick brown fox,jumps over the,lazy dog.
The punctuation characters exists in the string is: 3

Flowchart:

Exercise 27

Write a program in C to print only the string before new line character.

Note: isprint() will only print line one, because the newline character is not printable.

Sample Solution:

C Code:

#include<stdio.h>
#include<ctype.h>

int main()
        
{
    int ctr=0;
    char str[]=" The quick brown fox \n jumps over the \n lazy dog. \n";    
    printf("\n Print only the string before new line character:\n"); 
        
    printf("----------------------------------------------------\n");    
    while (isprint(str[ctr]))
    {
        putchar (str[ctr]);
  
             ctr++;
    }
    printf("\n\n");
    return 0;
}

Sample Output:

Print only the string before new line character:
----------------------------------------------------
The quick brown fox

Flowchart:

Exercise 28

Write a program in C to check whether a letter is lowercase or not.

C Programming: Check whether a letter is lowercase or not

Sample Solution:

C Code:

#include<stdio.h>
#include<ctype.h>

int
    main()
{
    char TestChar;
    printf("\n Check whether a letter is lowercase or not:\n");  
    printf("------------------------------------------------\n");    
     
    printf(" Input a character: "); 
    scanf( "%c", &TestChar );
    if( islower(TestChar) )
        printf( " The entered letter is a lowercase letter.
    \n" );
    else
        printf( " The entered letter is not a lowercase letter. \n" );
    return 0;
}

Sample Output:

Check whether a letter is lowercase or not:
------------------------------------------------
Input a character: w
The entered letter is a lowercase letter.

Flowchart:

Exercise 29

Write a program in C to read a file and remove the spaces between two words of its content.

C Programming: Remove the spaces between two words of its content

Sample Solution:

C Code:

#include<stdio.h>
#include<ctype.h>

int
    main()
{
    FILE * pfile;
    int a;
    printf("\n Remove the spaces between two words:\n");  
    printf("-----------------------------------------\n");    
    
// file.txt contain : the quick brown fox jumps over the lazy dog
    pfile=fopen ("file.txt","r");
    printf(" The content of the file is :\n The quick brown fox jumps over the lazy dog\n\n");   
    
    printf(" After removing the spaces the content is: \n");
    if (pfile)
    {
        do {
            a =
    fgetc (pfile);
            if ( isgraph(a) ) putchar (a);
        } while (a != EOF);
        fclose (pfile);
    }
  
     printf("\n\n");
    return 0;
}

Sample Output:

Remove the spaces between two words:
-----------------------------------------
The content of the file is:
The quick brown fox jumps over the lazy dog

After removing the spaces the content is:
Thequickbrownfoxjumpsoverthelazydog

Flowchart:

Exercise 30

Write a program in C to check whether a character is digit or not.

C Programming: Check whether a character is digit or not

Sample Solution:

C Code:

#include<stdio.h>
#include<ctype.h>

int
    main()
{
    char TestChar;
    printf("\n Check whether a character is digit or not:\n");  
    printf("----------------------------------------------\n");      
   
    printf(" Input a character: ");
    scanf( "%c", &TestChar );
    if( isdigit(TestChar) )
        printf( " The entered character is a digit. \n\n" );
    else
  
         printf( " The entered character is not a digit. \n\n" );
    return 0;
}

Sample Output:

Check whether a character is digit or not:
----------------------------------------------
Input a character: 8
The entered character is a digit.

Flowchart:

Exercise 31

Write a program in C to split string by space into words.

C Programming: Split string by space into words

Sample Solution:

C Code:

#include <stdio.h>
#include <string.h>
int main()
{
   
    char str1[100];
    char newString[10][10]; 
    int i,j,ctr;
       printf("\n\n Split string by space into words:\n");
       printf("---------------------------------------\n");  
     
 
    printf(" Input  a string: ");
    fgets(str1, sizeof str1, stdin);    
 
    j=0; ctr=0;
    for(i=0;i<=(strlen(str1));i++)
   
    {
        // if space or NULL found, assign NULL into newString[ctr]
        if(str1[i]==' '||str1[i]=='\0')
        {
           
    newString[ctr][j]='\0';
            ctr++;  //for next word
            j=0;    //for next word, init index to
    0
        }
        else
        {
            newString[ctr][j]=str1[i];
           
    j++;
        }
    }
    printf("\n Strings or words after split by space are:\n");
    for(i=0;i < ctr;i++)
       
    printf(" %s\n",newString[i]);
    return 0;
}

Sample Output:

Split string by space into words:
---------------------------------------
Input a string: this is a test string

Strings or words after split by space are:
this
is
a
test
string

Flowchart:

Exercise 32

Write a C programming to find the repeated character in a given string.

Sample Solution:

C Code:

#include<stdio.h>
#include
int ifexists(char p, char q[],  int v)
{
  
     int i;
    for (i=0; i<v;i++)
        if (q[i]==p) return (1);
    return (0);
}
int main()
{
    char string1[80],string2[80];
  
     int n,i,x;
    printf("Input a string: ");
    scanf("%s",string1);
    n=strlen(string1);
    string2[0]=string1[0];
    x=1;
    for(i=1;i
    < n;  i++)
    {
        if(ifexists(string1[i], string2, x))
        {
            printf("The first repetitive
    character in %s is: %c ", string1, string1[i]);
            break;
        }
        else
        {
  
             string2[x]=string1[i];
            x++;
        }
    }
    if(i==n)
       
    printf("There is no repetitive character in the string %s.", string1);
}

Sample Output:

Input a string: The first repetitive character in w3resource is: r

Flowchart:

Exercise 33

Write a C programming to count of each character in a given string.

Sample Solution:

C Code:

#include<stdio.h>
#include<string.h>
int if_char_exists(char c, char p[],  int x,
    int y[])
{
    int i;
    for (i=0; i<=x;i++)
    {
        if (p[i]==c)
        {
       
    y[i]++;
        return (1);
        }
    }
    if(i>x) return (0);
}
int main()
{
    char str1[80],chr[80];
  
     int n,i,x,ctr[80];
    printf("Enter a str1ing: ");
    scanf("%s",str1);
    n=strlen(str1);
    chr[0]=str1[0];
    ctr[0]=1;
    x=0;
  
     for(i=1;i < n;  i++)
    {
        if(!if_char_exists(str1[i], chr, x, ctr))
        {    
           
    x++;        
            chr[x]=str1[i];
            ctr[x]=1;
        }
  
     }
    printf("The count of each character in the string %s is \n", str1);
    for (i=0;i<=x;i++)
        printf("%c\t%d\n",chr[i],ctr[i]);
}

Sample Output:

Enter a str1ing: The count of each character in the string w3resource is
w    1
3    1
r    2
e    2
s    1
o    1
u    1
c    1

Flowchart:

Exercise 34

Write a C programming to convert vowels into upper case character in a given string.

Sample Solution:

C Code:

#include 
int main()
{
    char string1[255];
   
    int  i;
   printf("Input a sentence: ");
   gets(string1);
   printf("The original string:\n");
   puts(string1);
   i=0;
    while(string1[i]!='\0')
   
    {
        if(string1[i]=='a' ||string1[i]=='e' ||string1[i]=='i' ||string1[i]=='o' ||string1[i]=='u')
            string1[i]=string1[i]-32;
       
    i++;
    }
    printf("After converting vowels into upper case the sentence becomes:\n");
    puts(string1);
}

Sample Solution:

Input a sentence: The original string:
w3resource
After converting vowels into upper case the sentence becomes:
w3rEsOUrcE

C String Exercises

Description

Table of contents

C String Exercises

Exercise 1

Exercise 2

Exercise 3

Exercise 4

Exercise 5

Exercise 6

Exercise 7

Exercise 8

Exercise 9

Exercise 10

Exercise 11

Exercise 12

Exercise 13

Exercise 14

Exercise 15

Exercise 16

Exercise 17

Exercise 18

Exercise 19

Exercise 20

Exercise 21

Exercise 22

Exercise 23

Exercise 24

Exercise 25

Exercise 26

Exercise 27

Exercise 28

Exercise 29

Exercise 30

Exercise 31

Exercise 32

Exercise 33

Exercise 34

C String: Solutions

Exercise 1

Sample Solution:

Sample Output:

Flowchart:

Exercise 2

Sample Solution:

Sample Output:

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Exercise 3

Sample Solution:

Sample Output:

Flowchart:

Exercise 4

Sample Solution:

The program can also be written as below:

Sample Output:

Flowchart :

Exercise 5

Sample Solution:

Sample Output:

Flowchart:

Exercise 6

Sample Solution:

Sample Output:

Sample Output:

Flowchart:

Exercise 7

Sample Solution:

Sample Output:

Flowchart:

Exercise 8

Sample Solution:

Sample Output:

Flowchart:

Exercise 9

Sample Solution:

Sample Output:

Flowchart:

Exercise 10

Sample Solution:

Sample Output: