Check if two strings are same or not without using library functions Last Updated : 20 Mar, 2023 Comments Improve Suggest changes Like Article Like Report Given two strings S1 and S2, the task is to check whether they are the same or not without using string library functions. Examples: Input: S1 = ”GeeksForGeeks”, S2 = ”GeeksForGeeks”Output: TrueExplanation:S1 and S2 are the same strings Input: S1 = ”GeeksForGeeks”, S2 = ”GeeksforGeeks”Output: False Approach: Follow the steps below to solve the problem: Create a function compareStrings() that takes the two strings S1 and S2 as input parameters and does the following:If the lengths of S1 and S2 are different, return false.Store the length of S1 in a variable, say N.Traverse from 0 to N-1 using the variable i and do the following:If S1[i] is not equal to S2[i], return false.Return true at the end of the traversal. Below is the implementation of the above approach: C #include <stdbool.h> #include <stdio.h> // Function to calculate length of string int len(char* S) { // Variable for traversal int i = 0; // Traverse till null is reached while (S[i]) i++; return i; } // Function to check whether // two strings are same or not bool compareStrings(char S1[], char S2[]) { // If lengths of the two // strings are different if (len(S1) != len(S2)) return false; // Variable for traversal int i = 0; // Traverse till null is reached while (S1[i]) { if (S1[i] != S2[i]) return false; // Increment i i++; } return true; } // Driver Code int main() { // Input char S1[] = "GeeksForGeeks"; char S2[] = "GeeksForGeeks"; // Function Call bool ans = compareStrings(S1, S2); printf("%s", ans ? "True" : "False"); return 0; } C++ // C++ program for the above approach #include <iostream> #include <cstring> using namespace std; // Function to calculate length of string int len(char* S) { // Variable for traversal int i = 0; // Traverse till null is reached while (S[i]) i++; return i; } // Function to check whether // two strings are same or not bool compareStrings(char S1[], char S2[]) { // If lengths of the two // strings are different if (len(S1) != len(S2)) return false; // Variable for traversal int i = 0; // Traverse till null is reached while (S1[i]) { if (S1[i] != S2[i]) return false; // Increment i i++; } return true; } // Driver Code int main() { // Input char S1[] = "GeeksForGeeks"; char S2[] = "GeeksForGeeks"; // Function Call bool ans = compareStrings(S1, S2); cout << (ans ? "True" : "False"); return 0; } // This code is contributed by rishab Java // Java program to implement the above approach public class Main { // Function to calculate length of string public static int len(String S) { // Variable for traversal int i = 0; // Traverse till null is reached while (i < S.length()) i++; return i; } // Function to check whether // two strings are same or not public static boolean compareStrings(String S1, String S2) { // If lengths of the two // strings are different if (len(S1) != len(S2)) return false; // Variable for traversal int i = 0; // Traverse till null is reached while (i < S1.length()) { if (S1.charAt(i) != S2.charAt(i)) return false; // Increment i i++; } return true; } // Driver Code public static void main(String[] args) { // Input String S1 = "GeeksForGeeks"; String S2 = "GeeksForGeeks"; // Function Call boolean ans = compareStrings(S1, S2); System.out.println(ans ? "True" : "False"); } } // Contributed by adityashae15 Python3 # Function to check whether # two strings are same or not def compareStrings(S1, S2): # If lengths of the two # strings are different if (len(S1) != len(S2)): return False # Variable for traversal i = 0 # Traverse till null is reached while (i < len(S1)): if (S1[i] != S2[i]): return False # Increment i i += 1 return True # Driver Code if __name__ == '__main__': # Input S1 = "GeeksForGeeks" S2 = "GeeksForGeeks" # Function Call ans = compareStrings(S1, S2) print("True" if ans else "False") # This code is contributed by mohit kumar 29 JavaScript <script> function len(S) { // Variable for traversal let i = 0; // Traverse till null is reached while (i < S.length) i++; return i; } function compareStrings(S1,S2) { // If lengths of the two // strings are different if (len(S1) != len(S2)) return false; // Variable for traversal let i = 0; // Traverse till null is reached while (i < S1.length) { if (S1[i] != S2[i]) return false; // Increment i i++; } return true; } // Input let S1 = "GeeksForGeeks"; let S2 = "GeeksForGeeks"; // Function Call let ans = compareStrings(S1, S2); document.write(ans ? "True" : "False"); // This code is contributed by patel2127 </script> C# using System; using System.Collections.Generic; class GFG{ // Function to calculate length of string static int len(string S) { // Variable for traversal int i = 0; // Traverse till null is reached while (i < S.Length) i++; return i; } // Function to check whether // two strings are same or not static bool compareStrings(string S1, string S2) { // If lengths of the two // strings are different if (len(S1) != len(S2)) return false; // Variable for traversal int i = 0; // Traverse till null is reached while (i < S1.Length) { if (S1[i] != S2[i]) return false; // Increment i i++; } return true; } // Driver Code public static void Main() { // Input string S1 = "GeeksForGeeks"; string S2 = "GeeksForGeeks"; // Function Call bool ans = compareStrings(S1, S2); Console.Write(ans ? "True" : "False"); } } // This code is contributed by SURENDRA_GANGWAR OutputTrue Time Complexity: O(N)Auxiliary Space: O(1) Comment More infoAdvertise with us Next Article Check if two strings are same or not without using library functions G geeksforgeeks user Follow Improve Article Tags : Strings C Language DSA Practice Tags : Strings Similar Reads Check if two strings are same or not 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#, eq 7 min read Check if two numbers are equal without using comparison operators The following are not allowed to use Comparison Operators String function Examples: Input : num1 = 1233, num2 =1233Output : Same Input : num1 = 223, num2 = 233Output : Not Same Method 1: The idea is to use the XOR operator. 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