Java program to check whether string is palindrome or not

In earlier post we have discussed how to check whether a number is palindrome or not.In today’s post we shall check whether a string is palindrome or not.For this we shall use built in functions to reverse a string and then compare the reversal of string to given string.

Procedure:1. Take input from the user and store it in a variable.
2.Here we are going to call a function “reveresing” to find the reverse of the string.
3.At last we shall call the display function to show whether it is a palindrome or not.

Now we shall write a program and get a detailed explanation after this.

import java.util.*;
class finding
{
   String str,reverse_str="";
   int i;
  finding()
   {
     System.out.print("Enter any string:");
     Scanner in=new Scanner(System.in);
     str = in.nextLine();
    }
   void reversing()
    {
      int len_str = str.length();
      for(i=len_str-1;i>=0;i--)
          reverse_str = reverse_str+str.charAt(i);
      System.out.println("Hence reverse of the string is:"+reverse_str);
     }
    void display()
      {
         if(str.equals(reverse_str))
           System.out.println("Given string " + str + "  is palindrome");
         else
           System.out.println("Given string "+ str +" is not palindrome");
       }
}
        
class strpalin
{
     public static void main(String a[])
    {
       finding ob=new finding();
       ob.reversing();
       ob.display();
    }
}

Explanation:1. In the “reversing method” we are calculating the length of the given string.Then we are adding each letter of the given string to “reverse_str” variable.Each letter of the given string is obtained using “variable.charAt()” method.
For Ex: If the given string is “hello” then by using str.charAt(2) we get l as the output.Because of indexing of the string begins from 0.
3.Therefore a reverse of the given string is obtained.
4. Now we shall compare this reverse string with given string and display accurate message.
Output:
string_palindrome
You can download the program:download

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About Anuroop D

Very enthusiastic about technology and likes to share my knowledge through blogging. Has Bachelor's in Information Technology and currently pursuing my Master's in Computer Science.
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