PAT A 1081 Rational Sum

#include<iostream>
#include<algorithm>
using namespace std;

struct Fraction{
    long long up,down;
};

int (int a,int b)
{
    if(a<b)     swap(a,b);
    if(b==0)    return a;
    else        return (b,a%b);
}

Fraction reduction(Fraction a)
{
    if(a.down<0){
        a.up=-a.up;
        a.down=-a.down;
    }
    if(a.up==0)     a.down=1;
    else{
        int d=(abs(a.up),abs(a.down));
        a.up/=d;
        a.down/=d;
    }
    return a;
}

Fraction add(Fraction a,Fraction b)
{
    Fraction ans;
    ans.up=a.up*b.down+b.up*a.down;
    ans.down=a.down*b.down;
    return reduction(ans);
}

void show(Fraction a)
{
    if(a.down==1)       printf("%d\n",a.up);
    else if(abs(a.up)>a.down){
        printf("%d %d/%d\n",a.up/a.down,abs(a.up)%a.down,a.down);
    }else{
        printf("%d/%d\n",a.up,a.down);
    }
}

int main()
{
    int n;
    Fraction ans={0,1},temp;
    cin>>n;
    for(int i=0;i<n;i++){
        scanf("%lld/%lld",&temp.up,&temp.down);
        ans=add(ans,temp);
    }
    show(ans);
    return 0;
}

本地错了oj对了… code blocks dev-c++ 什么的就是这么玄学 习惯了习惯了