a1065 a+b and c (64bit)

Given three integers A, B and C in [−2​^63​​,2​^63​​], you are supposed to tell whether A+B>C.

The first line of the input gives the positive number of test cases, T (≤10). Then T test cases follow, each consists of a single line containing three integers A, B and C, separated by single spaces.

For each test case, output in one line Case #X: true if A+B>C, or Case #X: false otherwise, where X is the case number (starting from 1).

3
1 2 3 
2 3 4
9223372036854775807 -9223372036854775808 0 

Case #1: false 
Case #2: true 
Case #3: false

#include <bits/stdc++.h>

int main()
{
    int T, count = 1;
    scanf("%d", &T);
    long long A, B, C, result;
    while (T--)
    {
        scanf("%lld%lld%lld", &A, &B, &C);
        result = A + B;
        bool flag;
        
        if (A > 0 && B > 0 && result < 0)
            flag = true;
        //负溢出
        else if (A < 0 && B < 0 && result >= 0)
            flag = false;
        //没有溢出
        else if (result > C)
            flag = true;
        else
            flag = false;

        if (flag == true)
            printf("Case #%d: truen", count++);
        else
            printf("Case #%d: falsen", count++);
    }

    return 0;
}