【每天一道PAT】1001 A+B Format

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 −10​6​​≤a,b≤10​6​​. 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.

思路

计算得到两数总和后，将每位数字存入栈中。
再将栈中的数字依次打印出来，同时判断栈中剩下的数字整除是否为3，如果是打印“，”。

#include <stdio.h>
#include <stack>
using namespace std;
int main()
{
    int a, b, c;
    stack<int> st;
    scanf("%d%d",&a,&b);
    c = a+ b;
    if(c<0){printf("-"); c = 0-c;}
    do{
        st.push(c%10);
        c /=10;
    }while(c !=0);
    while(st.empty() == false)
    {
        printf("%d",st.top());
        st.pop();
        if((st.size()%3 ==0)&&(st.size()!=0)) printf(",");
    }

}