giving an integer N (2 <= N <= 20) and a real number M (0.5 < M <= 1), output all proper fractions whose numerator is less than N ,and denominator is equal to or less than N, and value is equal to or less than M.

input: an integer N, a real number M in the type of double, in one line seperated by blank space.

output: proper fractions, each occupies a line. The proper fractions with smaller denominators are in the front. Between two different fractions with same denominator, the one whose numerator is smaller comes first. There is a ‘\n’ after the final fraction number.

Sample:

input:

6 0.7

output:

1/2

1/3

2/3

1/4

1/5

2/5

3/5

1/6
 

答：

#include<stdio.h>
int IFhuzhi(int a, int b) { //a b互質當且僅當 b 與 a % b互質
  if (a % b != 0)
    return IFhuzhi(b, a % b);
  else
    if (b == 1)
      return 1;
    else
      return 0;
}
int main(void) {
  int N;
  double M;
  scanf("%d %lf", &N, &M);
  int a, b;
  for (b = 2; b <= N; ++b)
    for
 
 (a = 1; a <= b; ++a)
      if (a * 1.0 / b <= M && IFhuzhi(b, a) == 1)
        printf("%d/%d\n", a, b);
  return 0;
}