Fizzbuzz in C for console
I have my doubts that any method is significantly faster than another given the sink-hole of time that printf() is, but here is another approach

#define FB "FizzBuzz\n"
#define F "Fizz\n"
#define B "Buzz\n"
#define N "%d\n"

int main(void) {
  static const char *fmt[15] = {
      FB, N, N, F, N, B, F, N, N, F, B, N, F, N, N };
  for (int a = 1; a &lt;= 100; a++) {
    printf(fmt[a % 15], a);
  }
  return 0;
}