Program to reverse the string without string API

Q. Write a Java program to reverse a string without using any string API.

Answer:

StringBuilder class provides a reverse() method to reverse the string. But in this example, we are using loop and charAt() methods to reverse the given string.

ReverseString.java

import java.util.*;
class ReverseString
{
     public static void main(String args[])
     {
          String original, reverse = "";
          Scanner in = new Scanner(System.in);

          System.out.print("Enter a string to reverse: ");
          original = in.nextLine();

          int length = original.length();

          for ( int i = length - 1 ; i >= 0 ; i-- )
                 reverse = reverse + original.charAt(i);

          System.out.println("Reverse of entered string is: "+reverse);
     }
}


Output:

reverse string
▲