I have a simple code, part of which contains the calculation 800/1000, which seems to return a value of zero for some reason (even though I store it in a float variable). When I replace the calculation with the expected result (0.8) the code works as expected, I just wonder why the calculation doesn't produce the same result.
Both 800.0/1000 or ((float)800)/1000 will work.
The former works only with hardcoded constants, while the latter works also with variables:
int a = 800;
int b = 1000;
float c = ((float)a) / b;
A whole numbers like 800 or 1000 are integers, while a number like 800.4 is considered fractional and is treated as a float. Two integers divided gives an whole integer result, in your case 0. If one number in the division is an integer, and one is a float, the result is a float.
0, before converting it to float. If you want the expression computed as a float, then at least one argument must be a flost, e.g.800.0 / 1000. – jfpoilpret Jun 19 '15 at 4:33