In this tutorial you will learn about different ways to reverse string in java with examples.
For example:
Input: Hello World
Output: dlroW olleH
Ways to Reverse String in Java
Method 1:
This is the simplest method in which we iterator through given string from end character by character and append to new empty string.
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package com; public class ReverseStringJava { public static void main(String...s){ String str = "I love programming"; String strReverse = ""; System.out.println("Original String: " + str); for(int i = str.length() - 1; i >= 0; --i){ strReverse = strReverse + str.charAt(i); } System.out.println("Reversed String: " + strReverse); } } |
Output
Original String: I love programming
Reversed String: gnimmargorp evol I
Method 2:
It is also an iterative method in which we iterate through the string from start as well as end and keep swapping the characters. Below is the program to implement this.
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package com; public class ReverseStringJava { public static void main(String...s){ String str = "I love programming"; char strChars[], tempChar; System.out.println("Original String: " + str); strChars = str.toCharArray(); for(int i = 0, j = str.length()-1; i < str.length()/2; ++i, --j){ tempChar = strChars[i]; strChars[i] = strChars[j]; strChars[j] = tempChar; } System.out.print("Reversed String: "); for(char c : strChars){ System.out.print(c); } } } |
Method 3:
StringBuffer class provides a method reverse() to reverse a string. This is the fastest and most efficient way to reverse a string.
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package com; public class ReverseStringJava { public static void main(String...s){ String str = "I love programming"; StringBuffer strReverse = new StringBuffer(str); System.out.println("Original String: " + str); strReverse.reverse(); System.out.print("Reversed String: " + strReverse); } } |
Method 4:
In this method we first insert the characters of string in a linked list. Now reverse the linked list using Collections.reverse() method. Finally print the characters present in linked list.
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package com; import java.util.Collections; import java.util.LinkedList; public class ReverseStringJava { public static void main(String...s){ String str = "I love programming"; char strChars[] = str.toCharArray(); LinkedList<Character> list = new LinkedList<Character>(); System.out.println("Original String: " + str); for(char c : strChars){ list.add(c); } Collections.reverse(list); System.out.print("Reversed String: "); for(char c : list){ System.out.print(c); } } } |
Please mention in the comment section if you know any other way to reverse string in java.
Push each character onto a stack, then pop em back off.
Stack reverse = new Stack();
String testString = “I love programming in Java”;
char[] charArray = testString.toCharArray();
for(char c:charArray){
reverse.push(c);
}
String reversed = “”;
while(!reverse.isEmpty()){
reversed += (reverse.pop());
}
System.out.println(reversed.toString());
}
Thanks for mentioning this method, I will add it to the tutorial.