35>firstDigit

Find the leftmost digit that occurs in a given string. Example For inputString = "var_1__Int", the output should be firstDigit(inputString) = '1'; For inputString = "q2q-q", the output should be firstDigit(inputString) = '2'; For inputString = "0ss", the output should be firstDigit(inputString) = '0'.

code>>

char firstDigit(std::string inputString) {

std::regex r("[^0-9]");

return regex_replace(inputString, r, "").c_str()[0];

}