Why does rand() + rand() produce negative numbers?

Question

I observed that rand() library function when it is called just once within a loop, it almost always produces positive numbers.

for (i = 0; i <         


        

Answer 1

the reason i was adding was to avoid '0' as the random number in my code. rand()+rand() was the quick dirty solution which readily came to my mind.

A simple solution (okay, call it a "Hack") which never produces a zero result and will never overflow is:

x=(rand()/2)+1    // using divide  -or-
x=(rand()>>1)+1   // using shift which may be faster
                  // compiler optimization may use shift in both cases

This will limit your maximum value, but if you don't care about that, then this should work fine for you.