how to use find the index of first char string c++ code example

Example 1: find character in string c++

auto char_to_find = 'a'
if (str.find(char_to_find) != std::string::npos) {
    // character found
}

Example 2: c++ string contains

if (string1.find(string2) != std::string::npos) {
    std::cout << "found!" << '\n';
}