Strings and Object References in Java

The String class is used for text manipulation. As you read, you will learn different ways to create Strings, methods to manipulate Strings, the String concatenation operator '+', and about how Strings are immutable.

20. Another substring()



Answer:
ExpressionSubstringComment
String snake = "Rattlesnake";"Rattlesnake"Create original String
snake.substring(6)"snake"Characters starting at character 6 to the end
snake.substring(0)"Rattlesnake"The new substring contains all the characters of the original string
snake.substring(10)"e"Character 10 is the last one
snake.substring(11)""If beginIndex==length, an empty substring is created.
snake.substring(12) If beginIndex is greater than length, a
IndexOutOfBoundsException is thrown.




Another substring()





    









    





    

    

    

    

    

        

    

    

        

            

                
                    

                        Expression
                        Result
                    

                    

                        String source = "Subscription";
                        "Subscription"
                    

                    

                        source.substring(0,3)
                        "Sub"
                    

                    

                        source.substring(3,9)
                        "script"
                    

                    

                        source.substring(0,0)
                        ""
                    

                    

                        source.substring(0,1)
                        "S"
                    

                    

                        source.substring(0,source.length())
                        "Subscription"
                    

                
            


            

                
Here is another method of String objects:

            

        

    





    

        

            

                

                    
substring(int beginIndex, int endIndex)

                

            

        

    





    

        

            

                
This method creates a new String containing characters from the original string starting at beginIndex and ending at endIndex-1.

                
bugWarning: the character at endIndex is not included.

                
The length of the resulting substring is endIndex-beginIndex.

            

            

                
Here is a picture that shows the character numbering. The 'n' is character 11.
subscription

    




Question 20:
What does this code write?
    String stars = "*****" ;
int j = 1;
while ( j <= stars.length() )
{
  System.out.println( stars.substring(0,j) );
  j = j+1;
}