Programming language
This program asks the user his or her age and responds based on what the user typed. If the user typed something that is not a number, the program says so. If the user typed a number less than zero, the program says so. If the user says he or she is older than 100 years old, the program says "That's old!". If the user typed a correct age, the program says back to the user how old he or she is.