converting lowercase to uppercase in c++ code example

Example 1: convert all characters in string to uppercase c++

transform(str.begin(), str.end(), str.begin(), ::toupper);

Example 2: string to upper c++

std::string data = "This is a sample string.";
// convert string to upper case
std::for_each(data.begin(), data.end(), [](char & c){
c = ::toupper(c);
});