c++ check if something is in string code example

Example 1: check if character in string c++

std::string s = "hell[o";
if (s.find('[') != std::string::npos)
    ; // found
else
    ; //

Example 2: c++ contains

if (s1.find(s2) != std::string::npos) {
    std::cout << "found!" << '\n';
}

Example 3: find in string c++

size_t find (const string& str, size_t pos = 0) const;