C语言代码实现的万年历计算

#include 
  
   
#include 
   
     #include 
    
      int main(int a, char** date) { int year = 0, month = 0, day = 0, week; int d, i, dm, dy, m2; char WEEK[9]; if (a == 1) { printf ("\n ERROR! you forgot to enter the date you want to view\n"); exit (0); } i = 0; d = -1; while (date[1][i])/*遍历传入的参数日期，计算出year，month，day*/ { if ((date[1][i] == '/' || date[1][i] == '.') && d == -1) { d = 0; i++; continue; } if ((date[1][i] == '/' || date[1][i] == '.') && d == 0) { d = 1; i++; continue; } if (d == -1) { year = year * 10 + (date[1][i] - '0'); } if (d == 0) { month = month * 10 + (date[1][i] - '0'); } if (d == 1) { day = day * 10 + (date[1][i] - '0'); } i++; } if (month < 1 || month > 12) /*若月份传入错误数字*/ { printf ("\n ERROR! the entered MONTH is invalid\n"); exit (0); } if (year == 2000) { dy = 0; /*年引起的星期差为0个*/ m2 = 1; /*2月引起的星期差为1个*/ goto la_100; } if (year > 2000) { d = (year - 1 - 2000) / 4 - (year - 1 - 2000) / 100 + (year - 1 - 2000) / 400 + 1; } else { d = (year - 2000) / 4 - (year - 2000) / 100 + (year - 2000) / 400; } dy = (year - 2000) + d; /*** 该年 1月1号 到2000年1月1号的 " 星期差 " ***/ if((year % 4 == 0 && year % 100 != 0) || (year % 100 == 0 && year % 400 == 0)) { m2 = 1; } else { m2 = 0; /*** 该年是否润 ***/ } la_100: /**** la_100 ****/ /*** 该月以前的月所引起的 " 星期差 " ***/ switch (month) { case 1: dm = 0; month = 31; break; /*** month 在此存放该月天数 ***/ 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 (day < 0 || day > month) { printf ("\n ERROR! the entered DAY is invalid\n"); exit (0); } week = (dy + dm + day - 1 + 6) % 7; if(week < 0) { week += 7; } if (day > 0) /*** 判定查看类型 ***/ { 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 < week; i++) { printf (" "); } for (i = 1; i <= month; i++) { printf (" %2d ", i); week++; if (week % 7 == 0 && i != month) printf ("\n"); } printf ("\n *********************************\n"); printf ("\n OK!\n"); } return 0; }