Reverse a string in Java

Question

I have \"Hello World\" kept in a String variable named hi.

I need to print it, but reversed.

How can I do this? I understand there

Answer 1

public static String reverseIt(String source) {
    int i, len = source.length();
    StringBuilder dest = new StringBuilder(len);

    for (i = (len - 1); i >= 0; i--){
        dest.append(source.charAt(i));
    }

    return dest.toString();
}

http://www.java2s.com/Code/Java/Language-Basics/ReverseStringTest.htm

Answer 2

I am doing this by using the following two ways:

Reverse string by CHARACTERS:

public static void main(String[] args) {
    // Using traditional approach
    String result="";
    for(int i=string.length()-1; i>=0; i--) {
        result = result + string.charAt(i);
    }
    System.out.println(result);

    // Using StringBuffer class
    StringBuffer buffer = new StringBuffer(string);
    System.out.println(buffer.reverse());    
}

Reverse string by WORDS:

public static void reverseStringByWords(String string) {
    StringBuilder stringBuilder = new StringBuilder();
    String[] words = string.split(" ");

    for (int j = words.length-1; j >= 0; j--) {
        stringBuilder.append(words[j]).append(' ');
    }
    System.out.println("Reverse words: " + stringBuilder);
}

Answer 3

I tried, just for fun, by using a Stack. Here my code:

public String reverseString(String s) {
    Stack<Character> stack = new Stack<>();
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < s.length(); i++) {
        stack.push(s.charAt(i));
    }
    while (!stack.empty()) {
        sb.append(stack.pop());
    }
    return sb.toString();

}

Answer 4

It is very simple in minimum code of lines

public class ReverseString {
    public static void main(String[] args) {
        String s1 = "neelendra";
        for(int i=s1.length()-1;i>=0;i--)
            {
                System.out.print(s1.charAt(i));
            }
    }
}

Answer 5

One natural way to reverse a String is to use a StringTokenizer and a stack. Stack is a class that implements an easy-to-use last-in, first-out (LIFO) stack of objects.

String s = "Hello My name is Sufiyan";

Put it in the stack frontwards

Stack<String> myStack = new Stack<>();
StringTokenizer st = new StringTokenizer(s);
while (st.hasMoreTokens()) {
     myStack.push(st.nextToken());
}

Print the stack backwards

System.out.print('"' + s + '"' + " backwards by word is:\n\t\"");
while (!myStack.empty()) {
  System.out.print(myStack.pop());
  System.out.print(' ');
}

System.out.println('"');

Answer 6

It gets the value you typed and returns it reversed ;)

public static  String reverse (String a){
    char[] rarray = a.toCharArray();
    String finalvalue = "";
    for (int i = 0; i < rarray.length; i++)
    {
        finalvalue += rarray[rarray.length - 1 - i];
    }   
return finalvalue;

}