CODEWITHSUNDEEP
javaarraysnetbeans-8
h.harry
h.harry

Reputation: 13

Using for loops, how to reverse a string?

This code isn't working. Can you tell me what's wrong and why?

package exer0403e08;


public class EXER0403E08 {
    public static void main(String[] args) {
        String str= "hello";
        System.out.println(str);
        char[]strchar = str.toCharArray();
        int first;
        int last=5;

        System.out.println("The reversed is: ");
        for (first=1; first<=5; first++){
            strchar[first]=strchar[last];


            last--;

        } 
        str=String.valueOf(strchar);
        str=str.toUpperCase();
        System.out.println(str);


    }

}

The answer is "OLLO" and i want to make it "OLLEH".

Upvotes: 0

Views: 2152

Answers (3)

Eclipse
Eclipse

Reputation: 175

you can write your own method like this: 

    public static String reverse(String str)
     {
     String reversed = new String();

     for ( int j = str.length()-1; j >= 0; j-- )
         reversed += str.charAt(j);

     return reversed;
     }

and then try reverse("Hello");

Upvotes: 1

Suresh Atta
Suresh Atta

Reputation: 121998

You loop have several problems. And you misunderstood the array indexes.

You are iterating and modifying the same array. Hence the weird behaviour and indexces will start from zero for arrays.

So the fixed code will be 

public static void main(String[] args) {
        String str = "hello";
        System.out.println(str);
        char[] strchar = str.toCharArray();
        int first;
        int last = 4;

        System.out.println("The reversed is: ");
        for (first = 0; first < 5; first++) {
            strchar[first] = str.charAt(last);

            last--;

        }
        str = String.valueOf(strchar);
        str = str.toUpperCase();
        System.out.println(str);

    }

Update :

Demo link http://ideone.com/GfgDZ3

Upvotes: 1

Arun Shankar
Arun Shankar

Reputation: 2593

You have better methods in java to reverse string. Please check this answer :

You can use this:

new StringBuilder(hi).reverse().toString()

Or, for versions earlier than JDK 1.5, use java.util.StringBuffer instead of StringBuilder — they have the same API. Thanks commentators for pointing out that StringBuilder is preferred nowadays.

Upvotes: 0

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