在while循环中添加闰年中的日期检查

Hey guys I've got this while loop which is checking for a valid input from user for a date. I need to add a check to this while loop, if its not a leap year day cannot be more than 28 and if it is a leap year day cannot be more than 29 ONLY if month is february, meaning month = 2 .Hey guys I've got this while loop which is chec