C++ Programming Question- please help and explain

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// bool validDate(int) // // Return true if the std::string argument is a valid calendar date. // // The arguments always take the form of month, day, and year // as positive integers separated by / as in "mm/dd/yyyy". // // If the std::string argument does not express a proper date, return FALSE. // // Use static function std::stoi(std::string possibleInt) // that returns the integer value of the std::string argument // with the precondition that the std::string argument is a valid integer. // Example of stoi: // std::stoi("08") returns 8 and std::stoi("2021") returns 2021. // // Examples of valid function returns: // validDate("01/31/2016") returns true // validDate("12/31/2017") returns true // validDate("06/15/2018") returns true // validDate("02/28/2019") returns true // validDate("02/29/2019") returns false // validDate("2019/06/06") returns false bool isValidDate (std::string date) { // TODO: Complete this function return not true; }