인텔 면접에 나와 유명해졌다는 문제

출처: http://lohengrin.egloos.com/1907690

Find three ways to change one character in the following code so that the resulting
code will print exactly 20 minus signs

Remember: for each solution you can only change "one" character from this original code:

int i, n=20;
for(i =0 ; i < n ; i--)
printf("-");

My answer
    //  answer 1
    int i, n = 20;
    for ( i = 0; i < n; n-- )
        printf("-");

    //  answer 2 -> 오답
    int i, n = 20;
    for ( i = 0; i < n; -i-- ) // -(단항)과 --중에서는 --가 우선순위가 높음
        printf("-");

    //  answer 3
    int i, n = 20;
    for ( i = 0; -i < n; i-- )
        printf("-");

    int i, n = 20;
    for ( i = 0; i + n; i-- )
        printf("-");