PAT-1001 A+B Format (20 分) 注意零的特例

Calculate a+b and output the sum in standard format -- that is, the digits must be separated into groups of three by commas (unless there are less than four digits).

Input Specification:

Each input file contains one test case. Each case contains a pair of integers a and b where −106≤a,b≤106. The numbers are separated by a space.

Output Specification:

For each test case, you should output the sum of a and b in one line. The sum must be written in the standard format.

Sample Input:

-1000000 9

Sample Output:

-999,991

就是计算a+b然后输出的水题,要注意符号判断,如果为0的话就输出一个0就可以了.
做任何题都要小心结果会不会就是一个0,还有一个0不算是前导0.

#include <iostream>
#include <bits/stdc++.h>
#define de(x) cout<<#x<<" "<<(x)<<endl
using namespace std;

int a[10];
int cur=0;
int main()
{
    int n,m;
    scanf("%d%d",&n,&m);
    int sum=n+m;
    bool sign_flag=true;
    bool zero_flag=false;
    if(sum==0)zero_flag=true;
    if(sum<0)sign_flag=false,sum=-sum;///
    while(sum>0)
    {
        a[cur++]=sum%10;
        sum/=10;
    }
    if(!sign_flag)printf("-");
    int cnt=0;
    for(int i=cur-1;i>=0;i--)
    {
        printf("%d",a[i]);
        cnt++;
        if(i%3==0&&i!=0)
        {
            printf(",");
        }
    }
    if(zero_flag)printf("0");
    printf("
");

    return 0;
}