万年历的设计：要求:模仿现实生活中的挂历，能够显示年历、月历、日历，并具备退出功能。

当前页以系统当前日期的月份为准显示当前月的每一天(显示出日及对应的星期几)。

当系统日期变到下一月时,系统自动翻页到下一月。

万年历的程序流程图：主要程序流程图:具体对于月份和年份的程序图如下:上图为计算星期方法上图为打印日历程序图万年历的设计的程序源代码：#include <stdio.h>#include <stdlib.h>#include <ctype.h>void f(){int day,month,year,sum,leap,S;printf("\n请输入年月日\n");scanf("%d%d%d",&year,&month,&day);while(1){if((month>12||month<1)||(day>31||day<1)){printf("输入错误，重新输入");scanf("%d%d%d",&year,&month,&day);}else break;}switch(month){case 1:sum=0;break;case 2:sum=31;break;case 3:sum=59;break;case 4:sum=90;break;case 5:sum=120;break;case 6:sum=151;break;case 7:sum=181;break;case 8:sum=212;break;case 9:sum=243;break;case 10:sum=273;break;case 11:sum=304;break;case 12:sum=334;break;default:printf("data error");break;}sum=sum+day;if(year%400==0||(year%4==0&&year%100!=0))leap=1;else leap=0;if(leap==1&&month>2)sum++;S=(year-1+(year-1)/4-(year-1)/100+(year-1)/400+sum)%7; switch(S){case 1:printf("星期一\n");break;case 2:printf("星期二\n");break;case 3:printf("星期三\n");break;case 4:printf("星期四\n");break;case 5:printf("星期五\n");break;case 6:printf("星期六\n");break;case 0:printf("星期日\n");break;}}void g(){int i,j=1,k=1,a,b,month,year;printf("\n输入年月:\n");scanf("%d%d",&year,&month);while(1){if(month>12||month<1){printf("输入错误，重新输入");scanf("%d%d",&year,&month);}else break;}b=days_month(month,year);a=firstday (month,year);printf("*************************************\n"); printf(" Sun Mon Tue Wed Thu Fri Sat \n");if(a==7){for(i=1;i<=b;i++){printf("%4d",i);if(i%7==0){printf("\n");}}}if(a!=7){while (j<=4*a){printf(" ");j++;}for(i=1;i<=b;i++){printf("%4d",i);if(i==7*k-a){printf("\n");k++;}}}printf("\n*************************************\n");printf("\n");}int leap (int year){if(year%4==0&&year%100!=0||year%400==0)return 1;else return 0;}int days_month (int month,int year){if(month==1||month==3||month==5||month==7||month==8||month==10||month==12) return 31;if(month==4||month==6||month==9||month==11)return 30;if(month==2&&leap(year)==1) return 29;else return 28;}int firstday(int month,int year){int W;W=(1+2*month+3*(month+1)/5+year+year/4+year/400-year/100)%7+1;return W;}void h(){int i,j=1,k=1,a,b,month,year,g;printf("\n输入任意年:\n");scanf("%d",&year);for(g=0;g<=11;g++){month=g+1;b=days_month(month,year);a=firstday (month,year);printf("%d月\n",month);printf("*************************************\n");printf(" Sun Mon Tue Wed Thu Fri Sat \n");if(a==7){for(i=1;i<=b;i++){printf("%4d",i);if(i%7==0){printf("\n");}}}j=1;k=1;if(a!=7){while (j<=4*a){printf(" ");j++;}for(i=1;i<=b;i++){printf("%4d",i);if(i==7*k-a){printf("\n");k++;}}}printf("\n*************************************\n"); printf("\n");}}void main(){for(;;){switch(menu_select()){case 1:printf("输入年月日计算星期几\n");f();break;case 2:printf("打印任意日历\n");g();break;case 3:printf("打印任意年历\n");h();break;case 4:printf("谢谢使用!\n");exit(0);}}}int menu_select(){char S;int cn;printf("1.输入年月日计算星期几\n"); printf("2.打印任意月历\n");printf("3.打印任意年历\n");printf("4.谢谢使用! \n");printf("input 1-4:\n");do {S=getchar();cn=(int)S-48;}while(cn<0||cn>6);return cn;}万年历的运行结果截图万年历的日历功能的实现：月历功能的实现：年历功能的实现：11。