In C++, how do you convert the whole document to uppercase string?

I tried using the for loop, then convert the whole document to upper then print it out, but they are still in lowercase.

Can anyone help me with this?

I do rate the answer, so please answer it seriously.

REMEBER: the argument "document" in the parameter is a file, so please make a test case that is actually testing converting to uppercase with a file.

using namespace std; bool html_is_valid(const std::string &document) for(int i-0; idocument. size() ;i++){ toupper(document[i]); cout