Question

How do you compute a random number using rand() but only getting it between 000 and 999?

Answer 1

int foo = rand() % 1000;

Answer 2

Depends on what rand() returns.

If rand() returns an integer between 0 and the largest integer possible, then: rand() % 1000
If rand() returns a float or double at least 0 and less than 1, then: floor( rand() * (999 + 1) )