FILE 0-whatsmyname.c is a program that prints its name, followed by a new line.
FILE 1-args.c is a program that prints the number of arguments passed into it.
FILE 2-args.c a program that prints all arguments it receives.
FILE 3-mul.c is a program that multiplies two numbers.
FILE 4-add.c is a program that adds positive numbers.
FILE 100-change.c is a program that prints the minimum number of coins to make change for an amount of money.