Java Program to Reverse a String

In this article, we will understand how to reverse a string. String is a datatype that contains one or more characters and is enclosed in double quotes(“ ”). Reverse string is displaying the string backwards or from right to left.

Below is a demonstration of the same −

Suppose our input is −

The string is defined as: Java Program

The desired output would be −

The reversed string is: margorP avaJ

Algorithm

Step 1 - START
Step 2 - Declare two string values namely input_string and reverse_string, and a char value namely temp.
Step 3 - Define the values.
Step 4 - Iterating using a for-loop, assign the i’th character to temp and later assign the ‘temp + reverse_string’ to reverse_string value. I.e adding the first element of the string to the last position of the reverse_string. Store the value.
Step 5 - Display the result
Step 6 - Stop

Example 1

Here, we bind all the operations together under the ‘main’ function.

public class ReverseString {
   public static void main (String[] args) {
      String input_string= "Java Program", reverse_string="";
      char temp;
      System.out.println("The string is defined as: " + input_string);
      for (int i=0; i<input_string.length(); i++) {
         temp= input_string.charAt(i);
         reverse_string= temp+reverse_string;
      }
      System.out.println("\nThe reversed string is: "+ reverse_string);
   }
}

Output

The string is defined as: Java Program

The reversed string is: margorP avaJ

Example 2

Here, we encapsulate the operations into functions exhibiting object-oriented programming.

public class ReverseString {
   static void reverse(String input_string){
      String reverse_string = "";
      char temp;
      for (int i=0; i<input_string.length(); i++) {
         temp= input_string.charAt(i);
         reverse_string= temp+reverse_string;
      }
      System.out.println("\nThe reversed string is: "+ reverse_string);
   }
   public static void main (String[] args) {
      String input_string= "Java Program";
      System.out.println("The string is defined as: " + input_string);
      reverse(input_string);
   }
}

Output

The string is defined as: Java Program

The reversed string is: margorP avaJ