C programming. The FizzBuzz program [closed]

Answer 1

I would say that modulo is expensive while comparisons are cheap so only perform the modulo once. That would yield something like this.

int i;
for( i = 0; i!=100; ++i ) {
    bool bModThree = !(i % 3);
    bool bModFive = !(i % 5);

    if( bModThree || bModFive ) {
        if( bModThree ) {
            printf( "Fizz" );
        }
        if( bModFive ) {
            printf( "Buzz" );
        }
    } else {
        printf( "%d", i );
    }

    printf( "\n" );
}