日历实现

用C语言实现一个简单日历，可由编者自由选择年月进行生成，Dev C++软件上可顺利运行

#include "stdio.h"
int isleep(int i)
{
   if(i%4==0&&i%100!=0||i%400==0)
     return 1;
    else
      return 0;
    }
int main()
{
   int i,n,day=0,month,y,d,a=0,j,e=1,c;
    printf("Enter which year you want to display:");
    scanf("%d",&i);
    j=i;
    while(e==1)
 { i=j;
     while(e==1)
    {
      printf("Enter month in %d to display calendar(1-12):",i);
    scanf("%d",&month);
    if(month<1||month>12)
    {printf("ERROR---Enter month in range of(1-12)!");continue;}
    else
    { printf("****************************************************\n");break;}
    }
  for(y=2010;y<i;y++)
   {day=day+isleep(i)?366:365;}
  for(n=1;n<month;n++)
 {
    switch(n)
    {case 1:
    case 3:
    case 5:
    case 7:
    case 8:
    case 10:
    case 12:day=day+31;break;
    case 4:
    case 6:
    case 9:
    case 11:day=day+30;break;
    case 2:day=day+isleep(i)?29:28;break;}
    }
       switch(month)
   { case 1:
    case 3:
    case 5:
    case 7:
    case 8:
    case 10:
    case 12:d=31;break;
    case 4:
    case 6:
    case 9:
    case 11:d=30;break;
    case 2:isleep(i)?day==29:day==28;break;}
 printf("MON     TUE     WED     THU     FRI     SAT     SUN     \n");
day=(day-3)%7;
a=day+1;
for(i=1;i<=day;i++)
{
   putchar('\t');
++a;}
for(i=1;i<=d;i++)
 {printf("%d\t",i);
++a;
if(a%7==0)
	putchar('\n');}
putchar('\n');
printf("Would you like to display another month(y/n)?");
c=getchar();
  if(c=='y')
  {e=1;}
if(c=='n')
  {e=0;}
	}
return 0;
}