CODEWITHSUNDEEP
javastringcompare
Josh McCure
Josh McCure

Reputation: 11

Reverse and compare String

I have started to learn java and I've run into some trouble. Just wondering why my compare string function is not working and always returning true;

The purpose of the program is to take an input of a string, reverse the string and see if the string is the same as the original input (palindrome).

import java.util.Scanner;

public class palinedromeString {


    private static Scanner keyboard;

    public static void main(String[] args) {

        System.out.println("Please enter a Palindrome");
        keyboard = new Scanner(System.in);
        String input = keyboard.next();
        String original = input;

        System.out.println("You entered: " + original);
        System.out.println("Your String reversed is:" + " " + stringReverse(input));
        System.out.println(checkString(input, original));
    }

    public static String stringReverse(String a) {
        String result = "";

        for(int i = a.length()-1; i>=0; i--){
            result = result + a.charAt(i);
        }


        return result;
    }

    public static boolean checkString(String a, String b){

        if(b.equals(a)){
            return true;
        }
        else{
        return false;
        }
    }

}

Upvotes: 1

Views: 7993

Answers (4)

Riaz
Riaz

Reputation: 1

Here in checkString(input, original) method, both the parameter has same value, Hence it always returns true.
You have to pass original and reversed string like this:

String reversedStr = stringReverse(input);
checkString(reversedStr , original);

Upvotes: 0

sree
sree

Reputation: 543

You have different options.

  1. Assign the

    stringReverse(input)

to a variable like

input=stringReverse(input);

before checking

  1. Imesha Sudasingha's answer.

The thing is you are reversing the string into a different variable and it doesnot get reflected in the String you pass unless you explicitly assign it.

Upvotes: 0

Imesha Sudasingha
Imesha Sudasingha

Reputation: 3570

Because you are passing input and original to the checkString() method. those two hold the same values. It's obvious you get true always.

checkString(stringReverse(input), original);

You have to use the above instead.

Upvotes: 1

Elliott Frisch
Elliott Frisch

Reputation: 201437

stringReverse returns the reversed String (it doesn't operate in place). Update input and your code should work as expected. Something like,

input = stringReverse(input);
System.out.println("Your String reversed is:" + " " + input);

Also, checkString is equivalent to

return b.equals(a);

Upvotes: 1

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