Program to reverse a sentence

Write a program to reverse a sentence.

Examples:

Input: “Practice with GFG”
Output: “GFG htiw ecitcarP”

Input: “Programming is fun”
Output: “nuf si gnimmargorP”

Approach: To solve the problem, follow the below idea:

It can be observed that we can reverse a sentence by traversing over the original sentence in reverse order and then pushing the characters from the back to a new string. Finally, return the final string.

Step-by-step algorithm:

• Create a variable to store the reversed sentence.
• Traverse the original sentence from the last character to the first.
• Append each character to the reversed sentence.

Below is the implementation of the algorithm:

C++

#include <iostream>
using namespace std;

string reverseSentence(string sentence)
{
    string reversedString = "";
    for (int i = sentence.length() - 1; i >= 0; i--) {
        reversedString.push_back(sentence[i]);
    }
    return reversedString;
}

int main()
{
    string sentence = "Practice with GFG";
    cout << reverseSentence(sentence) << endl;

    return 0;
}

C

#include <stdio.h>
#include <string.h>

char* reverseSentence(const char* sentence) {
    int length = strlen(sentence);
    char* reversedString = (char*)malloc((length + 1) * sizeof(char));

    for (int i = length - 1, j = 0; i >= 0; i--, j++) {
        reversedString[j] = sentence[i];
    }

    reversedString[length] = '\0';
    return reversedString;
}

int main() {
    const char* sentence = "Practice with GFG";
    char* reversed = reverseSentence(sentence);

    printf("%s\n", reversed);

    free(reversed);  // Don't forget to free the allocated memory

    return 0;
}

Java

public class ReverseSentence {
    public static String reverseSentence(String sentence)
    {
        StringBuilder reversedString = new StringBuilder();

        for (int i = sentence.length() - 1; i >= 0; i--) {
            reversedString.append(sentence.charAt(i));
        }

        return reversedString.toString();
    }

    public static void main(String[] args)
    {
        String sentence = "Practice with GFG";
        System.out.println(reverseSentence(sentence));
    }
}

Python3

def reverse_sentence(sentence):
    reversed_string = ""
    for i in range(len(sentence) - 1, -1, -1):
        reversed_string += sentence[i]
    return reversed_string


if __name__ == "__main__":
    sentence = "Practice with GFG"
    print(reverse_sentence(sentence))

C#

using System;

class Program {
    static string ReverseSentence(string sentence)
    {
        char[] charArray = sentence.ToCharArray();
        Array.Reverse(charArray);
        return new string(charArray);
    }

    static void Main()
    {
        string sentence = "Practice with GFG";
        Console.WriteLine(ReverseSentence(sentence));
    }
}

Javascript

function reverseSentence(sentence) {
    return sentence.split('').reverse().join('');
}

const sentence = "Practice with GFG";
console.log(reverseSentence(sentence));

Output

GFG htiw ecitcarP

Time Complexity: O(N), where N is the length of the sentence.
Auxiliary Space: O(N)