我想写一个分数计算程式，但唔知错啲乜

复制内容到剪贴板代码:#include <cstdint>
#include <iostream>
using namespace std;

void calculate(int);

int main()
{
int num;

cin >> num;

if (num == 0)
{
return 1;
}

for (int i = 2; i < num; ++i)
{
cout << "1/" << i << '+';
}
cout << "1/" << num << '=';

calculate(num);

return 0;
}

uintmax_t GCD(uintmax_t a, uintmax_t b)
{
while (b && (a %= b) && (b %= a));
return a + b;
}

uintmax_t factorial(uintmax_t a)
{
uintmax_t result = 1;

while (a) result *= a--;

return result;
}

void calculate(int num)
{
int f = (int)factorial(num), s = 0, gcd;

for (int i = 2; i <= num; ++i)
{
s += f / i;
}

gcd = (int)GCD(s, f);

cout << (s / gcd) << '/' << (f / gcd);
}