Reverse String using a Loop

Initialize an empty string to store the reversed result.
Iterate through the original string in reverse order.
Append each character to the new string.
The new string is the reversed version of the original string.

Below is the implementation to reverse a string using loop in different programming languages:

C++

#include <iostream>
#include <string>
 
std::string reverseStringLoop(const std::string& inputStr) {
    std::string reversedStr;
    for (int i = inputStr.length() - 1; i >= 0; i--) {
        reversedStr += inputStr[i];
    }
    return reversedStr;
}
 
int main() {
    std::string originalStr = "w3wiki";
    std::string result = reverseStringLoop(originalStr);
    std::cout << result << std::endl;
    return 0;
}

C

#include <stdio.h>
#include <string.h>
 
void reverseStringLoop(char inputStr[]) {
    int length = strlen(inputStr);
    for (int i = length - 1; i >= 0; i--) {
        printf("%c", inputStr[i]);
    }
    printf("\n");
}
 
int main() {
    char originalStr[] = "w3wiki";
    reverseStringLoop(originalStr);
    return 0;
}

Java

public class ReverseStringLoop {
    public static String reverseStringLoop(String inputStr) {
        StringBuilder reversedStr = new StringBuilder();
        for (int i = inputStr.length() - 1; i >= 0; i--) {
            reversedStr.append(inputStr.charAt(i));
        }
        return reversedStr.toString();
    }
 
    public static void main(String[] args) {
        String originalStr = "w3wiki";
        String result = reverseStringLoop(originalStr);
        System.out.println(result);
    }
}

Python3

def reverse_string_loop(input_str):
    reversed_str = ""
    for char in input_str[::-1]:
        reversed_str += char
    return reversed_str
 
# Example usage:
original_str = "w3wiki"
result = reverse_string_loop(original_str)
print(result)

C#

using System;
 
class Program {
    static string ReverseStringLoop(string inputStr) {
        char[] charArray = inputStr.ToCharArray();
        Array.Reverse(charArray);
        return new string(charArray);
    }
 
    static void Main() {
        string originalStr = "w3wiki";
        string result = ReverseStringLoop(originalStr);
        Console.WriteLine(result);
    }
}

Javascript

function reverseStringLoop(inputStr) {
    let reversedStr = "";
    for (let i = inputStr.length - 1; i >= 0; i--) {
        reversedStr += inputStr[i];
    }
    return reversedStr;
}
 
// Example usage:
let originalStr = "w3wiki";
let result = reverseStringLoop(originalStr);
console.log(result);

Output

skeeGrofskeeG

Time Complexity: O(n)
Auxiliary Space: O(n) for storing the reversed string.

String Reverse in C/C++/Java/Python/JavaScript

String reverse or reverse a string means changing the position of each character of the given string to its opposite position from end, i.e. if a character is at position 1 then its new position will be String.length, similarly if a character is at position 2 then its new position will be String.length – 1, and so on.

String Reverse in C/C++/Java/Python/JavaScript

Given a string, write a program to reverse the string.

Input: original_string[] = Geeks
Output: string_reversed[] = skeeG

Input: original_string[] = w3wiki
Output: string_reversed[] = skeeGroFskeeG

Table of Content

Reverse String using a Loop:
Reverse String using inbuilt method
Reverse String using Recursion:
Reverse String using two pointers:
String Reverse String using Stack:

Tags:

#Reverse #DSA #Strings #Reverse #Strings

Reverse String using inbuilt method

Reverse String using a Loop

C++

C

Java

Python3

C#

Javascript

String Reverse in C/C++/Java/Python/JavaScript

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