edaBit-coding-challenges/Magic-Date/code.cpp

/*  You are to read each part of the date into its own integer 
 ~  type variable. The year should be a 4 digit number. 
 ~  You can assume the user enters a correct date (no error checking required).
 ~  Determine whether the entered date is a magic date. 
 ~  Here are the rules for a magic date:
mm * dd is a 1-digit number that matches the last digit of yyyy
or
mm * dd is a 2-digit number that matches the last 2 digits of yyyy
or
mm * dd is a 3-digit number that matches the last 3 digits of yyyy
The program should then display true if the date is magic,
or false if it is not.
*/
bool magic(std::string str) {
	char space = ' ';
	std::size_t firstspace = str.find(space);
	// find position of the SPACE following firstspace
	std::size_t secondspace = str.find(space,firstspace+1);
	// the month is everything before firstspace
	int month = std::stoi(str.substr(0,firstspace));
	// the day is everything between firstspace and secondspace
	int day = std::stoi(str.substr(firstspace,(secondspace-firstspace)));
	// the year is everything after the secondspace
	std::string year = (str.substr(secondspace+1,4));
	int ears = year[3]-'0';
	int decade = std::stoi(year.substr(2,2));
	int century = std::stoi(year.substr(1,3));
	// md is a misdirection otherwise known as MONTH*DAY
	int md = month*day;
	return md==ears || md==decade || md==century;
}