计算一年中的第几天

#include<iostream>
using namespace std;

int main()
{
 int year,month,day;
 int m[12]={31,28, 31,30,31,30,31,31,30,31,30,31};
 cout<<"请输入年月日：";
 cin>>year>>month>>day;
 if(year%400==0 || year%4==0 && year%100!=0)
  m[1]=29;
 int sumdays=0;
 for(int i=0;i<month-1;i++){
  sumdays+=m[i];
 }
 sumdays+=day;
 cout<<year<<"年"<<month<<"月"<<day<<"日是一年中的第"<<sumdays<<"天"<<endl;
 system("pause");
 return 0;
}

 

系统函数：

#include<iostream>
#include <stdio.h> 　　
#include <stddef.h> 　　
#include <time.h>
using namespace std;

int main()
{
	time_t tmBeginTime = time(NULL);
	struct tm *tmNowBegin = localtime(&tmBeginTime);
	if (NULL == tmNowBegin)
		return false;
	int nCreateYear = tmNowBegin->tm_year+1900;
	int nCreateMon = tmNowBegin->tm_mon+1;
	int nCreateDay = tmNowBegin->tm_mday;
	int nCreateYearDay = tmNowBegin->tm_yday;
	int nCreateWeek = tmNowBegin->tm_wday;
	cout<<nCreateYear<<","<<nCreateMon<<","<<nCreateDay<<","<<nCreateYearDay<<","<<nCreateWeek<<endl;
	system("pause");
	return 0;	
}