日曆程序



需求描述：任意輸入一個年份，如2011，格式化打印出此年份十二個月份的日曆。

程序比較簡單，不多說了，直接上C源碼，代碼已在VC6.0上驗證通過。

///////////////////////////////////////////////////////////////////////////////////////////////////////////

/*****************************************************************
 * 文件名：  日曆
 * 實現功能：實現年曆的打印
 * 作者：    韓立忠  2011.08.15
 ****************************************************************/

/************************* 引入的頭文件 *************************/

#include<stdio.h>
#include<stdlib.h>

/************************* 全局函數聲明 *************************/

unsigned is_leap(unsigned);                   // 判斷某年是否閏年
unsigned number_of_leap(unsigned);            // 判斷從基準年1900年起的閏年數
unsigned weekday_of_newyears_day(unsigned);   // 判斷某年元旦星期幾
unsigned days_of_month(unsigned, unsigned);   // 判斷某確定年月的天數

/**************************** 主函數 ****************************/

void main(void)
{
 unsigned year         = 0;
 unsigned month        = 0;
 unsigned day          = 0;
 unsigned weekday      = 0;
 unsigned i_week       = 0;
 unsigned day_of_month = 0;

 printf("Input Year: ");
 scanf("%d", &year);

 weekday = weekday_of_newyears_day(year);
 for (month = 1; month <= 12; month++)
 {
  printf("\nMONTH:%2d\n", month);
  printf("---------------------------------------------------\n");
  printf("SUN\tMON\tTWE\tWEN\tTHU\tFRI\tSAT\n");
  printf("---------------------------------------------------\n");

  for (i_week = 0; i_week < weekday; i_week++)
  {
   printf("   \t");
  }
  
  day_of_month = days_of_month(year, month);
  for (day = 1; day <= day_of_month; day++)
  {
   printf("%2d\t", day);
   weekday = (weekday + 1) % 7;
   if ((0 == weekday) && (day != day_of_month))
   {
    printf("\n");
   }
  }

  printf("\n---------------------------------------------------\n");
 }
}

/****************************************************************/

/* 判斷某年是否閏年 */
unsigned is_leap(unsigned year)
{
 if (((0 == year % 4) && ( year % 100 != 0)) || (0 == year % 400))
 {
  return 1;
 }
 return 0;
}

/* 判斷從基準年1900年起到指定年的閏年數 */
unsigned number_of_leap(unsigned year)
{
 unsigned count  = 0;
 unsigned i_year = 0;

 if (year < 1900)
 {
  printf("Input error! Year must larger than 1900!\n");
  exit(0);
 }

 for (i_year = 1900; i_year <= year; i_year += 4)
 {
  if (is_leap(i_year))
  {
   count++;
  }
 }
 return count;
}

/* 判斷某年元旦星期幾，已知基準年1900年元旦星期一 */
unsigned weekday_of_newyears_day(unsigned year)
{
 unsigned weekday = 0;
 weekday = year - 1900 + number_of_leap(year) + 1;
 if (is_leap(year))
 {
  weekday--;
 }
 weekday %= 7;
 return weekday;
}

/* 判斷某確定年月的天數 */
unsigned days_of_month(unsigned year, unsigned month)
{
 unsigned day = 0;
 if ((4 == month) || (6 == month) || (9 == month) || (11 == month))
 {
  day = 30;
 }
 else if (2 == month)
 {
  day = 28 + is_leap(year);
 }
 else
 {
  day = 31;
 }
 return day;
}

/* ************************* The End ************************** */