求助：题目测试用例正确，测试点1也运行正确，为什么直接全错？？

#include<iostream>
#include<ctype.h>
#include<string.h>
#include<vector>
#include <sstream>
using namespace std;

int main(){
    int n;
    cin >> n;
    char temp;
    string answer[60];
    string s[60];
    for (int i = 0; i < n+1;i++){
        getline(cin, s[i]);
    }
    for (int i = 1; i < n+1; i++)
    {
        vector<int> num;
        for (int j = 0; j < s[i].length(); j++)
        {
            if (isspace(s[i][j]))
            {
                num.push_back(j);
            }
        }
        string s1, s2, s3;
        int s4;
        if (num.size() == 2)
        {
            temp = s[i][0];
            s1 = string(s[i], num[0] + 1, num[1] - num[0] - 1);
            s2 = string(s[i], num[1] + 1, s[i].length() - num[1] - 1);
            answer[i].append(s1);
            if (temp == 'a')
            {
                answer[i].append("+");
                s4 = (atoi(s1.c_str()) + atoi(s2.c_str()));
            }
            if (temp == 'b')
            {
                answer[i].append("-");
                s4 = (atoi(s1.c_str()) - atoi(s2.c_str()));
            }
            if (temp == 'c')
            {
                answer[i].append("*");
                s4 = (atoi(s1.c_str()) * atoi(s2.c_str()));
            }
            answer[i].append(s2);
            answer[i].append("=");
            stringstream ss;
            ss << s4;
            ss >> s3;
            answer[i].append(s3);
            cout << answer[i] << endl<<answer[i].length();
            if(i<n) cout << endl;
        }
        if (num.size() == 1)
        {
            s1 = string(s[i], 0, num[0]);
            s2 = string(s[i], num[0] + 1, s[i].length() - num[0] - 1);
            answer[i].append(s1);
            if (temp == 'a')
            {
                answer[i].append("+");
                s4 = (atoi(s1.c_str()) + atoi(s2.c_str()));
            }
            if (temp == 'b')
            {
                answer[i].append("-");
                s4 = (atoi(s1.c_str()) - atoi(s2.c_str()));
            }
            if (temp == 'c')
            {
                answer[i].append("*");
                s4 = (atoi(s1.c_str()) * atoi(s2.c_str()));
            }
            answer[i].append(s2);
            answer[i].append("=");
            stringstream ss;
            ss << s4;
            ss >> s3;
            answer[i].append(s3);
            cout << answer[i] << endl
                 << answer[i].length();
            if(i<n) cout << endl;
        }
    }
}