// This code shows some unexpected results of java math operations
// Author: mhornick
// Date: 1/10/2013
package cs2710;

public class MathDemo {

	/**
	 * @param args - not used
	 */
	public static void main(String[] args) {

		// this code causes a positive integer value to overflow on addition
		int x = 0x7FFFFFFF; // 0111 1111 1111 1111 1111 1111 1111 1111
		System.out.println(x); // largest int in decimal format
		int y = x + 1;		// increment the largest int by 1
		System.out.println(y); // ...largest negative int is the result!

		// this code causes a negative integer value to overflow on subtraction
		x = 0x80000000;		// 1000 0000 0000 0000 0000 0000 0000 0000 (largest negative int)
		y = x-10;			// try to make it even more negative
		System.out.println(y); // ...we get a positive int as a result!
// Moral of the story: java does not generate errors on overflow in addition/subtraction!

		x = 0x0FFFFFFF;	// 268,435,455
		y = 0x0FFFFFFF; 
		int z = x*y;	// theoretical answer: 72,057,593,501,057,025 (0xFF FFFF E000 0001 - 56 bits!!)
		System.out.println(z); // we get a bogus negative result since only the first 32 bits were saved!
// Moral of the story: don't run with scissors!
		
	}
}