java question

Write a program that prompts the user to enter 3 integers and displays the greatest common divisor of these three numbers. The greatest common divisor will be the largest positive integer that divides all three numbers without leaving a remainder. If any of the parameter numbers is less than or equal to zero, then the program should print -1.

For example:

Input	Result
12 12 24	Enter a number1: Enter a number2: Enter a number3: The greatest common divisor is: 12
0 12 12	Enter a number1: Enter a number2: Enter a number3: The greatest common divisor is: -1

Write a program which prompts the user to a number of rows and a number of columns. The program prints a parallelogram star pattern. Note: you can assume that the two numbers will always be positive (i.e. greater than 1).

For example:

Input	Result
5 5	Enter number of rows: Enter number of columns: ***** ***** ***** ***** *****
6 3	Enter number of rows: Enter number of columns: *** *** *** *** *** ***