#include <stdio.h>#include <stdlib.h>#include <string.h>#define str "  SUN  MON TUE  WED  THU  FRI  SAT  " void menu();     //操作菜單int leap(int year);    //判斷某年是不是閏年int days_month(int year, int month);    //返回某月的天數int someday(int year, int month, int day);  //計算某天是星期幾void search_month(int year, int month);    //輸出某月的日歷void search_someday(int year, int month, int day);  //查詢某日是星期幾 int main(){ int i, year, month, day; int k1, k2, k3, k4;  //用于判斷輸入的數據和操作是否正確，1代表正確，0代表錯誤 int a = 1; menu(); do { printf("請輸入你要進行的操作(1-4):"); scanf_s("%d", &i); getchar(); switch (i) { case 1:  printf("請輸入你要查詢的年份："); scanf_s("%d", &year);  for (a; a <= 12; a++)  {  printf("/n/n---------*******  %d *******------------/n", a);  search_month(year, a);  }  printf("---------*********************------------/n/n/n");  break;   case 2:  printf("請輸入您所要查詢的相關信息./n");  printf("年份："); scanf_s("%d", &year);  printf("月份："); scanf_s("%d", &month);  k1 = 1;  while (k1)  {  if (month > 12 || month < 1)  {   printf("你輸入的月份有誤，請重新輸入!/n");   printf("月份:");   scanf_s("%d", &month);   if (month < 1 || month>12)  k1 = 1;  }  else k1 = 0;  }  search_month(year, month);  printf("---------*********************------------/n/n/n");  break;   case 3:  printf("請輸入你要查詢的日期/n");  printf("年份："); scanf_s("%d", &year);  printf("月份："); scanf_s("%d", &month);  k2 = 1;  while (k2)  {  if (month > 12 || month < 1)  {   printf("你輸入的月份有誤，請重新輸入!/n");   printf("月份:");   scanf_s("%d", &month);   if (month < 1 || month>12)  k2 = 1;  }  else k2 = 0;  }  //  printf("%d年%d月有%d天/n",year,month,days_month(year,month));   調試觀察輸入的日期是否有誤，可忽略  printf("日期："); scanf_s("%d", &day);  k3 = 1;  while (k3)  {  if (day > days_month(year, month) || day < 1)  {   printf("你輸入的日期有誤，請重新輸入!/n");   printf("日期:");   scanf_s("%d", &day);   if (day > days_month(year, month) || day < 1)  k3 = 1;  }  else k3 = 0;  }  search_someday(year, month, day);  printf("---------*********************------------/n/n/n"); break;   case 4:exit(0);  printf("---------*********************------------/n/n/n"); break;   default:  k4 = 1;  while (k4)  {  printf("你輸入的數據有誤，請重新輸入你要進行的操作(1-4):");  scanf_s("%d", &i);  if (i < 1 || i>4)  k4 = 1;  else k4 = 0;  }  break; } } while (i > 0 && i < 5); return 0;} void menu(){ int i = 1; printf("/n/n/t/t----------------------------------------/n"); printf("/t/t|--------------------------------------|/n"); printf("/t/t|      %d. 輸出某年的日歷     |/n", i); printf("/t/t|      %d. 輸出某月的日歷     |/n", i + 1); printf("/t/t|      %d. 查詢某日是星期幾    |/n", i + 2); printf("/t/t|      %d. 退出系統        |/n", i + 3); printf("/t/t|--------------------------------------|/n"); printf("/t/t----------------------------------------/n/n"); } int leap(int year){ if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0) return 1; else return 0;} int days_month(int year, int month){ int days_month; switch (month) { case 1: case 3: case 5: case 7: case 8: case 10: case 12: days_month = 31; break;  case 4: case 6: case 9: case 11:days_month = 30; break;  case 2: if (leap(year) == 1) {  days_month = 29; break; } else days_month = 28; break; } return days_month;} int someday(int year, int month, int day){ //該函數運用了特殊的計算公式，詳細可參見 http://blog.163.com/hexin_mars_blog/blog/static/248215040201571351115699/ int someday, m, n, i; //someday表示查詢的日子是星期幾 m = year - year / 1000 * 1000; n = m - m / 100 * 100 - 1;      //用于獲得年份的后兩位數 int days = 0; for (i = 1; i < month; i++) days = days + days_month(year, i); days = days + day; someday = (n + n / 4 - n / 100 + n / 400 + days) % 7; return someday;} void search_someday(int year, int month, int day){ char weekname[20]; switch (someday(year, month, day)) { case 0:strcpy_s(weekname, "星期天"); break; case 1:strcpy_s(weekname, "星期一"); break; case 2:strcpy_s(weekname, "星期二"); break; case 3:strcpy_s(weekname, "星期三"); break; case 4:strcpy_s(weekname, "星期四"); break; case 5:strcpy_s(weekname, "星期五"); break; case 6:strcpy_s(weekname, "星期六"); break; } printf("你所要查詢的日期是%s/n", weekname);} void search_month(int year, int month){ int i = 0, j, k = 0, m;   //j用于記錄某月的第一天是星期幾  m用于記錄某月的天數 k用于換行提示 char x[10] = "   "; m = days_month(year, month); j = someday(year, month, 1);  //輸出某月的日歷 printf("------------------------------------------/n"); printf("%s/n", str); for (; i < j; i++) { printf("%s", x); k++; } for (i = 1; i <= m; i++) { k++; if (k % 7 == 0) {  if (i < 10)  {  printf("  %d ", i);  printf("/n");  }  else if (i >= 10)  {  printf("  %d ", i);  printf("/n");  } } else {  if (i < 10)  {  printf("  %d ", i);  }  else if (i >= 10)  {  printf("  %d ", i);  } } } printf("/n------------------------------------------/n");} void exit(){ exit(0);}