Check if two strings are same or not

Try it on GfG Practice

Given two strings, the task is to check if these two strings are identical(same) or not. Consider case sensitivity.

Examples:

Input: s1 = “abc”, s2 = “abc” 
Output: Yes 

Input: s1 = “”, s2 = “” 
Output: Yes 

Input: s1 = “GeeksforGeeks”, s2 = “Geeks” 
Output: No 

Approach – By Using (==) in C++/Python/C#, equals in Java and === in JavaScript

This approach compares two strings to check if they are the same. It works by using the equality operator (==) to compare both strings character by character. If the strings are identical, it prints "Yes", otherwise, it prints "No". The comparison stops as soon as a mismatch is found, or if one string ends before the other. The program performs this comparison in a straightforward way without any extra steps, simply checking the content of the strings.

#include <bits/stdc++.h>
using namespace std;

// Function to compare both strings directly
bool areStringsSame(string s1, string s2) {
    return s1 == s2;
}

int main()
{
    string s1 = "abc";
    string s2 = "abcd";
  
    // Call the areStringsSame function to compare strings
    if (areStringsSame(s1, s2)) {
        cout << "Yes" << endl;
    }
    else {
        cout << "No" << endl;
    }

    return 0;
}

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

// Function to compare both strings directly
bool areStringsSame(const char* s1, const char* s2) {
    return strcmp(s1, s2) == 0;
}

int main() {
    const char* s1 = "abc";
    const char* s2 = "abcd";

    // Call the areStringsSame function to compare strings
    if (areStringsSame(s1, s2)) {
        printf("Yes\n");
    } else {
        printf("No\n");
    }

    return 0;
}

public class GfG {
    // Function to compare both strings directly
    public static boolean areStringsSame(String s1, String s2) {
        return s1.equals(s2);
    }

    public static void main(String[] args) {
        String s1 = "abc";
        String s2 = "abcd";

        // Call the areStringsSame function to compare strings
        if (areStringsSame(s1, s2)) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
}

# Function to compare both strings directly

def areStringsSame(s1, s2):
    return s1 == s2

if __name__ == '__main__':
    s1 = "abc"
    s2 = "abcd"

    # Call the areStringsSame function to compare strings
    if areStringsSame(s1, s2):
        print("Yes")
    else:
        print("No")

using System;

class GfG {
    // Function to compare both strings directly
    static bool areStringsSame(string s1, string s2) {
        return s1 == s2;
    }

    static void Main() {
        string s1 = "abc";
        string s2 = "abcd";

        // Call the areStringsSame function to compare strings
        if (areStringsSame(s1, s2)) {
            Console.WriteLine("Yes");
        } else {
            Console.WriteLine("No");
        }
    }
}

// Function to compare both strings directly
function areStringsSame(s1, s2) {
    return s1 === s2;
}

const s1 = "abc";
const s2 = "abcd";

// Call the areStringsSame function to compare strings
if (areStringsSame(s1, s2)) {
    console.log("Yes");
} else {
    console.log("No");
}

No

Time Complexity: O(n)
Auxiliary Space: O(1)

Approach – By Using String Comparison Functions

In this approach, the program compares two strings to check if they are identical. It uses the strcmp function, which compares the strings character by character. If the strings are exactly the same, strcmp returns 0, indicating no difference between them. If the strings are different, strcmp returns a non-zero value. Based on this result, the program prints "Yes" if the strings match and "No" if they don’t. The comparison stops as soon as a mismatch is found or the strings end.

#include <bits/stdc++.h>

using namespace std;

// Function to compare two strings using strcmp
bool areStringsSame(char s1[], char s2[]) {
    return strcmp(s1, s2) == 0;
}

int main() {
    char s1[] = "hello";
    char s2[] = "hello";

    // Call the areStringsSame function to compare strings
    if (areStringsSame(s1, s2)) {
        cout << "Yes" << endl;
    } else {
        cout << "No" << endl;  
    }

    return 0;
}

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

// Function to compare two strings using strcmp
bool areStringsSame(char s1[], char s2[]) {
    return strcmp(s1, s2) == 0;
}

int main() {
    char s1[] = "hello";
    char s2[] = "hello";

    // Call the areStringsSame function to compare strings
    if (areStringsSame(s1, s2)) {
        printf("Yes\n");
    } else {
        printf("No\n");  
    }

    return 0;
}

import java.util.Arrays;

class GfG {
    // Function to compare two strings using equals
    public static boolean areStringsSame(String s1, String s2) {
        return s1.equals(s2);
    }

    public static void main(String[] args) {
        String s1 = "hello";
        String s2 = "hello";

        // Call the areStringsSame function to compare strings
        if (areStringsSame(s1, s2)) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
}

# Function to compare two strings using ==
def areStringsSame(s1, s2):
    return s1 == s2

s1 = "hello"
s2 = "hello"

# Call the areStringsSame function to compare strings
if areStringsSame(s1, s2):
    print("Yes")
else:
    print("No")

using System;

class GfG {
    // Function to compare two strings using Equals
    static bool areStringsSame(string s1, string s2) {
        return s1.Equals(s2);
    }

    static void Main() {
        string s1 = "hello";
        string s2 = "hello";

        // Call the areStringsSame function to compare strings
        if (areStringsSame(s1, s2)) {
            Console.WriteLine("Yes");
        } else {
            Console.WriteLine("No");
        }
    }
}

// Function to compare two strings using localeCompare
function areStringsSame(s1, s2) {
    return s1.localeCompare(s2) === 0;
}

let s1 = "hello";
let s2 = "hello";

// Call the areStringsSame function to compare strings
if (areStringsSame(s1, s2)) {
    console.log("Yes");
} else {
    console.log("No");
}

Yes

Time Complexity: O(n)
Auxiliary Space: O(1)

Approach – By Writing your Own Method

In this approach, the program compares two strings by first checking if their lengths are the same. If the lengths differ, the strings cannot be identical, so it returns false. If the lengths are the same, it then compares each character of the two strings one by one. If any mismatch is found, it returns false, indicating the strings are not the same. If no differences are found throughout the comparison, it returns true, meaning the strings are identical.

#include <bits/stdc++.h>

using namespace std;

bool areStringsEqual(string &s1, string &s2) {
  
    // Compare lengths first
    if (s1.length() != s2.length()) {
        return false;
    }

    // Compare character by character
    for (size_t i = 0; i < s1.length(); ++i) {
        if (s1[i] != s2[i]) {
            return false; 
        }
    }

    return true; 
}

int main() {
    string s1 = "hello";
    string s2 = "hello";

    if (areStringsEqual(s1, s2)) {
        cout << "Yes" << endl; 
    } else {
        cout << "No" << endl;  
    }

    return 0;
}

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

bool areStringsEqual(const char *s1, const char *s2) {
    // Compare lengths first
    if (strlen(s1) != strlen(s2)) {
        return 0;
    }

    // Compare character by character
    for (size_t i = 0; i < strlen(s1); ++i) {
        if (s1[i] != s2[i]) {
            return 0;
        }
    }

    return 1;
}

int main() {
    const char *s1 = "hello";
    const char *s2 = "hello";

    if (areStringsEqual(s1, s2)) {
        printf("Yes\n");
    } else {
        printf("No\n");
    }

    return 0;
}

public class GfG {
    public static boolean areStringsEqual(String s1, String s2) {
        // Compare lengths first
        if (s1.length() != s2.length()) {
            return false;
        }

        // Compare character by character
        for (int i = 0; i < s1.length(); i++) {
            if (s1.charAt(i) != s2.charAt(i)) {
                return false;
            }
        }

        return true;
    }

    public static void main(String[] args) {
        String s1 = "hello";
        String s2 = "hello";

        if (areStringsEqual(s1, s2)) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
}

def are_strings_equal(s1, s2):
    # Compare lengths first
    if len(s1) != len(s2):
        return False

    # Compare character by character
    for i in range(len(s1)):
        if s1[i] != s2[i]:
            return False

    return True

s1 = "hello"
s2 = "hello"

if are_strings_equal(s1, s2):
    print("Yes")
else:
    print("No")

function areStringsEqual(s1, s2) {
    // Compare lengths first
    if (s1.length !== s2.length) {
        return false;
    }

    // Compare character by character
    for (let i = 0; i < s1.length; i++) {
        if (s1[i] !== s2[i]) {
            return false;
        }
    }

    return true;
}

const s1 = "hello";
const s2 = "hello";

if (areStringsEqual(s1, s2)) {
    console.log("Yes");
} else {
    console.log("No");
}

Yes

Time Complexity: O(n)
Auxiliary Space: O(1)

RishabhPrabhu

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Article Tags :

• C Language
• DSA
• School Programming
• Strings
• school-programming

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Practice Tags :

• Strings