代码为;

#include <iostream>
#include <sstream>
#include <fstream>
#include <string>
#include <vector>

int main()
{
	std::vector<std::string> identity;
	std::string temp;
	std::ifstream file("in.txt");
	while(getline(file, temp) && temp != "0")
	{
		identity.push_back(temp);
	}
	for (size_t i = 0; i < identity.size(); i++)
	{
		if (identity[i].size() != 18)
		{
			std::cout << 1<<std::endl;
			continue;
		}
		for (int j = 0; j < 17; j++)
		{
			if (identity[i][j] < '0' && identity[i][j] > '9')
			{
				std::cout << 2 <<std::endl;
				continue;
			}
		}

		if (identity[i][17] != 'x' && (identity[i][17] < '0' || identity[i][17] > '9'))
		{
			std::cout << 3 <<std::endl;
			continue;
		}

		//年
		std::string tempYear;
		for (int j = 0; j < 4; j++)
		{
			tempYear += identity[i][6 + j];
		}
		int year = atoi(tempYear.c_str());
		if (year < 1900 || year > 2100)
		{
			std::cout << 4<<std::endl;
			continue;
		}

		//月
		std::string tempMonth;
		for (int j = 0; j < 2; j++)
		{
			tempMonth += identity[i][10 + j];
		}
		int month = atoi(tempMonth.c_str());
		if (month < 1 || month > 12)
		{
			std::cout << 5 <<std::endl;
			continue;
		}

		//day
		std::string tempDay;
		for (int j = 0; j < 2; j++)
		{
			tempDay += identity[i][12 + j];
		}
		int day = atoi(tempDay.c_str());
		if (day < 1 || day > 31)
		{
			std::cout << 6 << std::endl;
			continue;
		}
		if (month == 4 || month == 6 || month == 9 || month == 11 )
		{
			if (day == 31)
			{
				std::cout << 6 <<std::endl;
				continue;
			}
		}

		if (month == 2)
		{
			if ( !((year % 4 == 0 && year % 100 != 0) 
				|| (year % 100 == 0 && year % 400 == 0)))
			{
				if (day == 29)
				{
					std::cout << 6 <<std::endl;
					continue;
				}

			}
		}
		std::cout<<0 <<std::endl;
	}
    system("pause");
	return 0;
}