Question

The following code seems to always generate wrong result. I have tested it on gcc and windows visual studio. Is it because of float overflow or something else? Thanks in advance:)

#include <stdio.h>
#define N 51200000
int main()
{
 float f = 0.0f;
 for(int i = 0; i < N; i++)
  f += 1.0f;
 fprintf(stdout, "%f\n", f);
 return 0;
}

Answer 1

float only has 23 bits of precision. 512000000 requires 26. Simply put, you do not have the precision required for a correct answer.