## Input-Output Exercises

### Solutions

##### Exercise 1

Write a C program that convert a temperature from Centigrade to Fahrenheit.

The centigrade scale, which is also called the Celsius scale, was developed by Swedish astronomer Andres Celsius. In the centigrade scale, water freezes at 0 degrees and
boils at 100 degrees. The centigrade to Fahrenheit conversion formula is:

C = (5/9) * (F - 32)

where F is the Fahrenheit temperature.

**Sample Solution**

C Code:

#include<stdio.h>

float temp_f; /* degrees fahrenheit */

float temp_c; /* degrees centigrade */

char line_text[50]; /* a line of input */

int main(){

printf("Input a temperature (in Centigrade): ");

fgets(line_text,sizeof(line_text), stdin);

sscanf(line_text,"%f",&temp_c);

temp_f =((9.0/5.0)* temp_c)+32.0;

printf("%f degrees Fahrenheit.\n", temp_f);

return(0);

}

Sample Output:

Input a temperature (in Centigrade): 45

113.000000 degrees Fahrenheit.

**Flowchart**

##### Exercise 2

Write a C program that calculates the volume of a sphere.

A sphere is a perfectly round geometrical object in three-dimensional space that is the surface of a completely round ball.

In three dimensions, the volume inside a sphere is derived
to be V = 4/3*π*r3 where r is the radius of the sphere

**Sample Solution**

C Code:

#include<stdio.h>

float myradius; /* radius of the sphere */

float myvolume; /* volume of the sphere (to be computed) */

char line_text[50]; /* a line from the keyboard */

/* the value of pi to 50 places, from wikipedia */

constfloat PI =3.14159265358979323846264338327950288419716939937510;

int main(){

printf("Input the radius of the sphere : ");

fgets(line_text,sizeof(line_text), stdin);

sscanf(line_text,"%f",&myradius);

myvolume =(4.0/3.0)* PI *(myradius * myradius * myradius);/* volumn=(4/3) * pi * r^3*/

printf("The volume of sphere is %f.\n", myvolume);

return(0);

}

Sample Output:

Input the radius of the sphere: 2.56

The volume of sphere is 70.276237.

**Flowchart**

##### Exercise 3

Write a C program that prints the perimeter of a rectangle to take its height and width as input.

Pictorial Presentation:

**Sample Solution**

C Code:

#include<stdio.h>

int main(){

float rec_width; /* width of the rectangle */

float rec_height; /* height of the rectangle */

float rec_perimeter; /* perimeter (to be computed) */

printf("Input the height of the Rectangle : ");

sscanf(line_text,"%f",&rec_height);

printf("Input the width of the Rectangle : ");

sscanf(line_text,"%f",&rec_width);

rec_perimeter =2.0*(rec_height + rec_width);/* perimeter = 2 * ( width + height )*/

printf("Perimeter of the Rectangle is : %f\n", rec_perimeter);

return0;

}

Sample Output:

Input the height of the Rectangle: 5

Input the width of the Rectangle: 7

Perimeter of the Rectangle is: 24.000000

**Flowchart**

##### Exercise 4

Write a C program that converts kilometers per hour to miles per hour.

Pictorial Presentation:

**Sample Solution**

C Code:

#include<stdio.h>

float kmph; /* kilometers per hour */

float miph; /* miles per hour (to be computed) */

char line_text[50]; /* a line from the keyboard */

int main()

{

printf("Input kilometers per hour: ");

fgets(line_text, sizeof(line_text), stdin);

sscanf(line_text,"%f",&kmph);

miph =(kmph *0.6213712);

printf("%f miles per hour\n", miph);

return(0);

}

Sample Output:

Input kilometers per hour: 15

9.320568 miles per hour

**Flowchart**

##### Exercise 5

Write a C program that takes hours and minutes as input, and calculates the total number of minutes.

Pictorial Presentation:

**Sample Solution**

C Code:

#include<stdio.h>

int hrs; /* given number of hours */

int mins; /* given number of minutes */

int tot_mins; /* total number of minutes (to be computed) */

constintMINaHOUR=60; /* number of minutes in an hour */

char line_text[50]; /* line of input from keyboard */

int main(){

printf("Input hours: ");

fgets(line_text,sizeof(line_text), stdin);

sscanf(line_text,"%d",&hrs);

printf("Input minutes: ");

fgets(line_text,sizeof(line_text), stdin);

sscanf(line_text,"%d",&mins);

tot_mins = mins +(hrs *MINaHOUR);

printf("Total: %d minutes.\n", tot_mins);

return(0);

}

Sample Output:

Input hours: 5

Input minutes: 37

Total: 337 minutes.

**Flowchart**

##### Exercise 6

Write a program in C that takes minutes as input, and display the total number of hours and minutes.

Pictorial Presentation:

**Sample Solution**

C Code:

#include<stdio.h>

int tot_mins;/* given number of minutes */

int hrs; /* number of hours (to be computed) */

int mins; /* number of minutes (to be computed) */

constintMINaHOUR=60; /* number of minutes in an hour */

char line_text[50]; /* line of input from keyboard */

int main(){

printf("Input minutes: ");

fgets(line_text,sizeof(line_text), stdin);

sscanf(line_text,"%d",&tot_mins);

hrs =(tot_mins /MINaHOUR);

mins =(tot_mins %MINaHOUR);

printf("%d Hours, %d Minutes.\n", hrs, mins);

return(0);

}

Sample Output:

Input minutes: 546

9 Hours, 6 Minutes.

**Flowchart**

##### Exercise 7

Write a program in C that reads a firstname, lastname and year of birth and display the names and the year one after another sequentially.

Pictorial Presentation:

**Sample Solution**

C Code:

#include<stdio.h>

int main()

{

char firstname[20], lastname[20];

int bir_year;

printf("Input your firstname: ");

scanf("%s", firstname);

printf("Input your lastname: ");

scanf("%s", lastname);

printf("Input your year of birth: ");

scanf("%d",&bir_year);

printf("%s %s %d\n", firstname, lastname, bir_year);

return0;

}

Sample Output:

Input your firstname: Tom

Input your lastname: Davis

Input your year of birth: 1982

Tom Davis 1982

**Flowchart**

##### Exercise 8

Write a program in C to calculate the sum of three numbers with getting input in one line separated by a comma.

Pictorial Presentation:

**Sample Solution**

C Code:

#include<stdio.h>

int num1,num2,num3; /* declaration of three variables */

int sum;

char line_text[50]; /* line of input from keyboard */

int main()

{

printf("Input three numbers separated by comma: ");

fgets(line_text,sizeof(line_text), stdin);

sscanf(line_text,"%d, %d, %d",&num1, &num2,&num3);

sum = num1+num2+num3;

printf("The sum of three numbers: %d\n", sum);

return(0);

}

Sample Output:

Input three numbers separated by comma: 5,10,15

The sum of three numbers: 30

**Flowchart**

##### Exercise 9

Write a C program to perform addition, subtraction, multiplication and division of two numbers.

Pictorial Presentation:

**Sample Solution**

C Code:

#include<stdio.h>

int main()

{

int num1, num2;

int sum,sub, mult, mod;

float div;

/*

* Read two numbers from user separated by comma

*/

printf("Input any two numbers separated by comma: ");

scanf("%d,%d", &num1,&num2);

/*

* Performs all arithmetic operations

*/

sum = num1 + num2;

sub= num1 - num2;

mult = num1 * num2;

div =(float)num1 / num2;

mod = num1 % num2;

/*

* Prints the result of all arithmetic operations

*/

printf("The sum of the given numbers: %d\n", sum);

printf("The difference of the given numbers: %d\n", sub);

printf("The product of the given numbers: %d\n", mult);

printf("The quotient of the given numbers: %f\n", div);

printf("MODULUS = %d\n", mod);

return0;

}

Sample Output:

Input any two numbers separated by comma: 10,5

The sum of the given numbers: 15

The difference of the given numbers: 5

The product of the given numbers: 50

The quotient of the given numbers: 2.000000

MODULUS = 0

**Flowchart**

##### Exercise 10

Write a C program to find the third angle of a triangle if two angles are given.

Pictorial Presentation:

**Sample Solution**

C Code:

#include<stdio.h>

int main()

{

int ang1, ang2, ang3;/*are three angles of a triangle */

/* Read two angles of the triangle from user separated by comma*/

printf("Input two angles of triangle separated by comma : ");

scanf("%d, %d",&ang1,&ang2);

ang3 =180-(ang1 + ang2); /* Calculates the third angle */

printf("Third angle of the triangle : %d\n", ang3);

return0;

}

Sample Output:

Input two angles of triangle separated by comma : 50,70

Third angle of the triangle : 60

**Flowchart**