poj3979

简单题

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;

int gcd(int x, int y)
{
    if (!x || !y)
        return x > y ? x : y;
    for (int t; t = x % y; x = y, y = t)
        ;
    return y;
}

int main()
{
    //freopen("t.txt", "r", stdin);
    int a, b, c, d, e, f, g;
    char op;
    while (scanf("%d/%d%c%d/%d", &a, &b, &op, &c, &d) != EOF)
    {
        f = b * d;
        if (op == '+')
            e = a * d + b * c;
        else
            e = a * d - b * c;
        g = gcd(abs(e), abs(f));
        e /= g;
        f /= g;
        if (f < 0)
        {
            e *= -1;
            f *= -1;
        }
        if (f == 1)
            printf("%d\n", e);
        else
            printf("%d/%d\n", e, f);
    }
    return 0;
}