Thread: Issue with typecasting float to int

Code:

float offset = ( i / 1000 ) * 256;

i is an int, 1000 is an int, 256 is an int...

i/1000 = 0 (int)
0 * 256 = 0 (int)
After this sub-expression 0 is converted to float (0.0f)...

If you want a floating point calculation of 1/1000 you should use ONE of the terms (dividend or divisor) as a float:

Code:

float offset = ( i / 1000.0f ) * 256;

This will promote i to float, and the result of i / 1000.0f will be a float, which will promote 256 to a float as well:

Code:

#include <stdio.h>


int main()
{
  int i;

  for ( i = 0; i <= 10; i++ )
  {
    // NOTE: dividing by 1000.0f will promote i and 256 to float.
    float offset = ( i / 1000.0f ) * 256;

    printf ( "%d\n", ( int )offset );
  }

  return 0;
}