Design an algorithm that will prompt for and accept a four-digit representation of the year (for example, 2003). Your program...

Design an algorithm that will prompt for and accept a four-digit representation of the year (for example, 2003). Your program is to determine if the year provided is a leap year and print a message to this effect on the screen. Also print a message on the screen if the value provided is not exactly four numeric digits. Continue progressing until a sentinel of 0000 is entered.