weird math bug?

Newbie & Debugging Questions
#1

This code returns -119… Wtf?


		System.out.println(158 * 15000000/
					16100000);

it prints -119 why does it do that?

Thanks in advance.

#2

try;

System.out.println("2147483647+1="+(2147483647+1));
2147483647+1=-2147483648

2147483647=0x7FFFFFFF
-2147483648=0x80000000

Signed ints use the top bit to indicate a -ve number.

Edit: Fix your problem with a cast to long;

System.out.println((long)158 * 15000000/16100000);
#3

I thought java didnt use signed/unsigned?

And yes, your code worked. Thanks alot :smiley:

#4

NP! Java doesn’t use unsigned - always a pain with bytes: 127+1=-128!