萬年歷，可查看任何日期對應的星期

注意:以下程序需要以命令行格式運行。例如，編譯後的可執行文件被命名爲filename。如果您想查看某個2002/02/01，請輸入文件名2002/01，如果您想查看2002年1月，請輸入文件名2002/01/0。

if((year % 4 = = 0 & & year % 100！= 0)| |(year % 100 = = 0 & & year % 400 = = 0))
m2 = 1；否則m2 = 0；

la_100:

　　
　　switch (month)
　　{
　　case 1: dm=0; month=31; break;
　　case 2: dm=3; month=d==1? 29:28; break;
　　case 3: dm=3 m2; month=31; break;
　　case 4: dm=6 m2; month=30; break;
　　case 5: dm=1 m2; month=31; break;
　　case 6: dm=4 m2; month=30; break;
　　case 7: dm=6 m2; month=31; break;
　　case 8: dm=2 m2; month=31; break;
　　case 9: dm=5 m2; month=30; break;
　　case 10: dm=m2; month=31; break;
　　case 11: dm=3 m2; month=30; break;
　　case 12: dm=5 m2; month=31; break;
　　}
　　if (daymonth)
　　{ printf ("\n ERROR! the entered DAY is invalid\n"); exit (0); }
　　week=(dy dm day-1 6)%7; if(week

　　if (day>0)
　　{
　　switch (week)
　　{
　　case 0: strcpy (WEEK,"SUNDAY"); break;
　　case 1: strcpy (WEEK,"MONDAY"); break;
　　case 2: strcpy (WEEK,"TUESDAY"); break;
　　case 3: strcpy (WEEK,"WEDNESDAY"); break;
　　case 4: strcpy (WEEK,"THURSDAY"); break;
　　case 5: strcpy (WEEK,"FRIDAY"); break;
　　case 6: strcpy (WEEK,"SATURDAY"); break;
　　}
　　printf ("\n this day is %s \( %d \)\n\n OK!\n",WEEK,week);
　　}
　　else
　　{
　　week= week%7;
　　printf ("\n the calender of this month as following\n");
　　printf ("\n *********************************\n");
　　printf (" SUN MON TUE WEN THU FRI STA\n");
　　for (i=0;i　　for (i=1;i