C :

#include<stdio.h> 
int fun(int y,int m,int d); 
int isrunnian(int n) 
{ 
    if(n%4 == 0&&n%100 != 0 || n%400 == 0) 
    return 1; 
    else return 0; 
} 
int main() 
{ 
    int t,y,m,d;  
    int allday;
    scanf("%d",&t);
    while(t--)
    {
    	scanf("%d%d%d",&y,&m,&d); 
	    allday = fun(y,m,d); 
	    printf("%d年%d月%d日是星期",y,m,d);
	    if(y > 1979)
	    switch(allday%7) 
	    { 
	        case 0:printf("一");break; 
	        case 1:printf("二");break; 
	        case 2:printf("三");break; 
	        case 3:printf("四");break; 
	        case 4:printf("五");break; 
	        case 5:printf("六");break; 
	        case 6:printf("日");break; 
	    }
	    else
	    switch(allday%7) 
	    { 
	        case 0:printf("一");break; 
	        case 1:printf("日");break; 
	        case 2:printf("六");break; 
	        case 3:printf("五");break; 
	        case 4:printf("四");break; 
	        case 5:printf("三");break; 
	        case 6:printf("二");break; 
	    }
	    printf("\n");
    }
    return 0; 
} 
int fun(int y,int m,int d) 
{
    int i,dy,allday = 0; 
    int a[12]={31,29,31,30,31,30,31,31,30,31,30,31}; 
    int b[12]={31,28,31,30,31,30,31,31,30,31,30,31};
	if(y > 1979)
	{
		dy = 1980;
		while(dy < y)
		{
			if(isrunnian(dy))
			allday += 366;
			else
			allday += 365;
			dy++;
		} 
		if(isrunnian(y))
		for(i = 0;i < m - 1;i++)
		allday += a[i];
		else
		for(i = 0;i < m - 1;i++)
		allday += b[i];
		allday += d;
	}
    else
    {
    	dy = 1979;
    	while(dy > y)
    	{
    		if(isrunnian(dy))
			allday += 366;
			else
			allday += 365;
			dy--;
    	}
		if(isrunnian(y))
		for(i = 11;i >= m;i--)
		allday += a[i];
		else
		for(i = 11;i >= m;i--)
		allday += b[i];
		allday += (a[m-1]-d);
		if(isrunnian(y)&&m == 2)
		allday--;
    }
    return allday; 
}

C++ :

#include<iostream>
#include<cstdio>
using namespace std;

int main()
{
	//freopen("1.txt","r",stdin);
	//freopen("2.txt","w",stdout);
	
	int year,month,day;
	int M;
	cin >> M;
	while(M--) {
		
		cin >> year >> month >> day;	// 输入年月日
		
		bool leap = year%400 == 0 || year%100 != 0 && year%4 == 0;	// 判断闰年
		int total = year-1980+(year-1980+3)/4;	// 求平（闰)年累计的总天数
		for(int i = month-1; i > 0; i--) {
			switch(i) {
				case 1:case 3:case 5:case 7:case 8:case 10:total += 31; break;
				case 4:case 6:case 9:case 11:total += 30; break;
				case 2:total += leap ? 29 : 28;
			}
		} 
		total += day;	// 当个月的天数 
		int week = 1;	// 起始日是1979-12-31是星期一
		week = (week+total)%7;	// 求得星期几
		
		cout << year << "年" << month << "月" << day << "日" << "是星期";
		switch(week) {
			case 0:cout << "日" << endl; break; 
			case 1:cout << "一" << endl; break; 
			case 2:cout << "二" << endl; break; 
			case 3:cout << "三" << endl; break; 
			case 4:cout << "四" << endl; break; 
			case 5:cout << "五" << endl; break; 
			case 6:cout << "六" << endl; break; 
		} 			 
	}
	
	return 0;
}