PAT A 1065 正溢和负溢

#include<cstdio>
using namespace std;
typedef long long ll;
int main()
{
    int n;
    ll a,b,c;
    scanf("%d",&n);
    for(int i = 1; i<=n; ++i)
    {
        scanf("%lld%lld%lld",&a,&b,&c);
        ll sum = a+b;
        bool f = true;
        printf("Case #%d: ",i);
        if(a>0&&b>0&&sum<=0);
        else if(a<0&&b<0&&sum>=0) f = false;
        else if(sum<=c) f = false;
        puts(f?"true":"false");
    }
    return 0;
}