[SWEA-D1] C++ 2056. 연월일 달력

#include<iostream>
using namespace std;

int main(int argc, char** argv)
{
	int test_case;
	int T;
	cin>>T;
	
    int dayOfmonth[13] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
    
	for(test_case = 1; test_case <= T; ++test_case)
	{
        int y, m, d;
            
        string ymd;
        cin >> ymd;
        int y = atoi(ymd.substr(0, 4).c_str()); // c_str: string을 char로 변환
        int m = atoi(ymd.substr(4, 2).c_str());
        int d = atoi(ymd.substr(6, 2).c_str());
        
        if(m>=1 && m<=12 && d<=31 && d<=dayOfmonth[m])
        {
            cout << "#" << test_case << " " << ymd.substr(0, 4) << "/" << ymd.substr(4, 2) << "/" << ymd.substr(6, 2) << endl;
        } else
            {
				cout << "#" << test_case << " " << "-1" << endl;
            }
    }
	return 0;
}