How to determine if a string is a number with C++?

Question

I\'ve had quite a bit of trouble trying to write a function that checks if a string is a number. For a game I am writing I just need to check if a line from the file I am r

Answer 1

Here's another way of doing it using the library:

bool is_integer(const std::string & s){
    return std::regex_match(s, std::regex("[(-|+)|][0-9]+"));
}