# include <stdio.h>int leapyear(int year){if((year%4 == 0 &&year%100 != 0)||(year%400 == 0))return(1);elsereturn(0);}int week(int y,int m,int d){int sum=0,i,x;int a[12]={31,28,31,30,31,30,31,31,30,31,30,31};for(i=0;i<m-1;i++)sum=sum+a[i];sum=sum+d;if((leapyear(y)==1)&&(m>=2))sum=sum+1;x=(5+(y+1)+(y-1)/4-(y-1)/100+(y-1)/400+sum)%7;return x;}int max(int y,int m){ int a[12]={31,28,31,30,31,30,31,31,30,31,30,31};if(leapyear(y)==1)a[1]=a[1]+1;return a[m-1];}void main(){int choice;int year,month,day;printf("*******************万年历********************\n");printf(" 1.查询某年某月某日是星期几\n");printf(" 2.是否为闰年\n");printf(" 3.查询某月的最大天数\n"); printf(" 4.打印某年某月的月历\n");printf(" 0.退出\n");printf("*********************************************\n");do{printf("请输入一个指令："); scanf("%d",&choice); switch(choice){case 0:printf("退出系统");break; case 1:{int a;printf("请输入要查询的日期：\n"); scanf("%d,%d,%d",&year,&month,&day);printf("%d年%d月%d日是星期",year,month,day);a=week(year,month,day);switch(a){case 1:printf("一\n");break; case 2:printf("二\n");break; case 3:printf("三\n");break; case 4:printf("四\n");break; case 5:printf("五\n");break; case 6:printf("六\n");break; case 0:printf("天\n");break;}}break;case 2:{printf("请输入要查询的年份:\n");scanf("%d",&year);if(leapyear(year)==1) printf("%d是闰年\n",year); else printf("%d不是闰年\n",year);}break;case 3:{int b;printf("请输入年月:\n");scanf("%d,%d",&year,&month);b=max(year,month); printf("%d年%d月的最大天数是:%d\n",year,month,b);}break;case 4:{int c,t=1;int d[100]={0};printf("请输入年份:\n");scanf("%d",&year);printf("请输入月份:\n");scanf("%d",&month); printf("SUN MON TUE WED THU FRI SAT :\n"); printf("*******************%d年%d月********************\n",year,month); c=week(year,month,1);for(int h=0;h<c;h++)printf(" ");for(int i=c;i<=max(year,month)+c-1; i++){d[i]=t;t++;} for(int j=c;j<=max(year,month)+c-1; j++){printf("%2d ",d[j]);if((j+1)%7==0)printf("\n");}printf("\n************************************************\n");}}}while(choice!=0);}
