how to find if a string is subset of another string c++ code example

Example 1: how to check string contains char in c++

std::string s = "Hello";
if (s.find('e') != std::string::npos)
    cout << "Found";
else
    cout << "Not Found";

Example 2: find substring in string c++

std::string parentstring = "Hello Agnosticdev, I love Tutorials";
std::string substring = "Agnosticdev";
auto index = parentstring.find(substring);