How to Compare Two Substrings in a Character Array in C++?

In C++, character arrays are used to store a sequence of characters also known as strings. A Substring is a continuous sequence of characters within a string. In this article, we will learn how we can compare two substrings in a character array in C++.

Examples: 

Input:
string: "Hello World"
Substring1: "Hello"  Substring 2: "World"

Output: 
Substrings are not equal.

Compare Two Substrings in a Character Array in C++

To compare two substrings in a character array in C++, we can use the std::substr() method to extract the substrings we want to compare from the character array. Then, we can compare the two substrings using the equality operator(==) .

C++ Program to Compare two Substrings in a Character Array

The following program illustrates how we can compare two substrings in a character array in C++:

// C++ Program to illustrate how we can compare two
// substrings in a character array
#include <iostream>
#include <string>
using namespace std;

int main()
{
    // Initializing a character array
    char charArray[] = "GeeksforGeeks";

    // Extracting  substrings from the character array
    string substring1 = string(charArray).substr(0, 5);
    string substring2 = string(charArray).substr(8, 12);

    // Compare  the substrings
    if (substring1 == substring2) {
        cout << "The substrings are equal." << endl;
    }
    else {
        cout << "The substrings are not equal." << endl;
    }

    return 0;
}

The substrings are equal.

Time Complexity: O(N + K) where N is the length of the character array and K is the average length of the substring.
Auxiliary Space: O(K)