Determine if a string contains a char in C++

This post will discuss how to determine if a string contains a char in C++.

1. Using `string::find`

We can use the string::find function to search for a specific character in a string. It returns the index of the first instance of the character or string::npos if the character is not present. The following is a simple example demonstrating its usage.

#include <iostream>

#include <string>

int main()

{

std::string str = "C++20";

char c = '+';

if (str.find(c) != std::string::npos) {

std::cout << "Character found" << std::endl;

} else {

std::cout << "Character not found" << std::endl;

}

return 0;

}

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Output:

Character found

2. Using `basic_string::contains`

Starting from C++23, we can use the much-awaited std::basic_string::contains function to checks if the string contains the given substring. It returns true if the string contains the specified substring, false otherwise.