Which of these pieces of code is faster in Java?

Question

a) for(int i = 100000; i > 0; i--) {}

b) for(int i = 1; i < 100001; i++) {}

The answer is t

Answer 1

The bottom line is that for any non-performance critical application, the difference is probably irrelevant. As others have pointed out there are times when using ++i instead of i++ could be faster, however, especially in for loops any modern compiler should optimize that distinction away.

That said, the difference probably has to do with the underlying instructions that get generated for the comparison. Testing if a value is equal to 0 is simply a NAND NOR gate. Whereas testing if a value is equal to an arbitrary constant requires loading that constant into a register, and then comparing the two registers. (This probably would require an extra gate delay or two.) That said, with pipelining and modern ALUs I'd be surprised if the distinction was significant to begin with.