用C语言编写的万年历

// VC++6.0 编译通过
# include <stdio.h>
# include <windows.h>
int year; //定义年份为全局变量
int check_year (int year) //判断输入的年份是否为闰年
{
if(year%4 == 0 && year%100 !=0 || year%400 == 0)
return 1;
else
return 0;
}
int check_month (int month) //判断每月的天数
{
switch (month)
{
case 0: return 0; break;
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12: return 31; break;
case 4:
case 6:
case 9:
case 11: return 30; break;
case 2: //闰年二月和平年二月的天数
{
if (check_year(year) == 1)
return 29;
else
return 28;
} break;
}
}
int firstday (int year,int month) //判断某年某月的第一天为星期几{
static int w=0;
w += check_month(month-1);
return ((year-1)+((year-1)/4)-((year-1)/100)+((year-1)/400)+1+w)%7;
}
main ()
{
int month=1,day,i,flag;
printf ("请输入要打印的年份: ");
scanf ("%d",&year);
printf ("\n");
printf (" %d年\n\n",year);
for (month=1;month<=12;month++)
{
printf (" %d月\n",month);
printf (" ---------------------------\n");
printf (" SUN MON TUE WED THU FRI SET\n");
printf (" ---------------------------\n");
flag = firstday(year,month);
for (i=0;i<flag;i++) //每月第一天所在星期几之前的位置用空格输出printf (" ");
for (day=1;day<=check_month(month);day++) //按格式输出日历
{
printf ("%4d",day);
if ((day+flag)%7 == 0)
printf ("\n");
}
printf("\n\n");
system("pause");
printf("\n");
}
}。