按照日期推算出星期几

悠悠 2022-06-14 09:16 490阅读 0赞

#include <stdio.h>
    
    char WeekList[ ][7]={"星期一", "星期二", "星期三", "星期四", "星期五", "星期六", "星期日"};
    
    void dateToWeek(int y,int m, int d)
    {
        if (m==1 || m==2)
        {
            m+=12;
            y--;
        }
        int iWeek=(d+2*m+3*(m+1)/5+y+y/4-y/100+y/400)%7;
        printf("%s\n", WeekList[iWeek]);
    }
    int main()
    {
        int year=0,month=0,day=0;
        
    	printf("请输入日期(2000-1-1):");
        scanf("%d-%d-%d",&year,&month,&day);
        dateToWeek(year,month,day);
    
        return 0;
    }
    
    /*
    基姆拉尔森计算公式
    W= (d+2*m+3*(m+1)/5+y+y/4-y/100+y/400) mod 7
    在公式中d表示日期中的日数，m表示月份数，y表示年数。
    注意：在公式中有个与其他公式不同的地方：
    把一月和二月看成是上一年的十三月和十四月
    */

我以前的笨办法是这样的：

#include <iostream>
    
    using namespace std;
    int main(int argc, char *argv[])
    {
    	int Month_Day[12] = {31,28,31,30,31,30,31,31,30,31,30,31};
    	const char Week[7][7] = {"星期一", "星期二", "星期三", "星期四", "星期五", "星期六", "星期日"};
    	int year,month,day;
    	int STDyear = 2010, STDmonth = 10, STDday = 31, STDweekday = 6;//STDweekday是参考日期的星期几，对应Week下标 
    	int Alldays = 0;		//与标准日期的间隔总天数 
    	int diff_Flag = 0;		//0表示输入时间小于标准时间，1表示大于 
    	int WeekToday = 0;
    	
    	
    	scanf("%d-%d-%d", &year, &month, &day);
    	//cout<<year<<month<<day;
    	if((year < STDyear) || ((year == STDyear) && (month <= STDmonth)))
    	{
    		diff_Flag = 0;
    		while((year != STDyear) || (month != STDmonth) || (day != STDday))
    		{
    			Alldays++;
    			day++;
    			if(2 == month)
    			{
    				if(((year % 4 ==0) && (year % 100 != 0)) || (year % 400 == 0))
    				{
    					Month_Day[1] = 29;//闰年2月29天 
    				}
    				else
    				{
    					Month_Day[1] = 28;
    				}
    			}
    			if(day > Month_Day[month - 1])//前面考虑闰年 
    			{
    				day = 1;
    				month++;
    				if(month > 12)
    				{
    					month = 1;
    					year++;
    				}
    			}
    		}
    	}
    	else
    	{
    		diff_Flag = 1;
    		while((year != STDyear) || (month != STDmonth) || (day != STDday))
    		{
    			Alldays++;
    			day--;
    			if(2 == month)
    			{
    				if(((year % 4 ==0) && (year % 100 != 0)) || (year % 400 == 0))
    				{
    					Month_Day[1] = 29;//闰年2月29天 
    				}
    				else
    				{
    					Month_Day[1] = 28;
    				}
    			}
    			if(day < 1)
    			{
    				month--;
    				if(month < 1)
    				{
    					month = 12;
    					year--;
    				}
    				day = Month_Day[month - 1];//前面考虑闰年 
    			}
    		}
    	}
    	cout<<"间隔"<<Alldays<<"天"<<endl;
    	if(diff_Flag == 0)
    	{
    		WeekToday = STDweekday - (Alldays % 7);
    	}
    	else
    	{
    		WeekToday = (Alldays + STDweekday) % 7;
    	}
    	cout<<Week[WeekToday]<<endl;
    	
    	return 0;
    }