没有给定输入的结束条件题目a+b

#include
using namespace std;
#include
int main()
{
string str1, str2;
string str3, str4;
int num1, num2,temp1=-1,temp2=-1;
while (cin>>str1>>str2)
{
str3 = "";
str4 = "";

    for (int i = 0; i <= str1.size(); i++)
    {
        if (str1[i] == ','||str1[i]=='\0')
        {
        
            str3 = str3 + str1.substr(temp1 + 1, i - temp1 - 1);
                temp1 = i;

        }
    }
    
    for (int i = 0; i <= str2.size(); i++)
    {
        if (str2[i] == ',' || str2[i] == '\0')
        {

            str4 = str4 + str2.substr(temp2 + 1, i - temp2 - 1);
            temp2 = i;
        }
    }
    
    num1 = stoi(str3);
    num2 = stoi(str4);
    cout << num1 + num2 << endl;
}

}

为什么我不能输入第二组数据呀，一输入第二组数据编译器就报错