万年历C语言程序（可以查月，年星期几）

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

int a[12]=  {31,28,31,30,31,30,31,31,30,31,30,31};
int b[12]=  {31,29,31,30,31,30,31,31,30,31,30,31};
int c[101]= {366,365,365,365,366,365,365,365,366,365,365,365,
 366,365,365,365,366,365,365,365,366,365,365,365,
 366,365,365,365,366,365,365,365,366,365,365,365,
 366,365,365,365,366,365,365,365,366,365,365,365,
 366,365,365,365,366,365,365,365,366,365,365,365,
 366,365,365,365,366,365,365,365,366,365,365,365,
 366,365,365,365,366,365,365,365,366,365,365,365,
 366,365,365,365,366,365,365,365,366,365,365,365,
 366,365,365,365,366};
char d[7]=  {'7','1','2','3','4','5','6'};
int    year,month,day;
char  *DateToPediod(int year,int month,int day);
void   PrintEachMonth(int year,int month);
void   PrintEachYear(int year);
int    DayToNow(int year,int month,int day);
bool   IsFesterval(int year, int month,int day);

void main()
{  
bool flag =true;

//do{
switch(getchar())
{
case 'a':

     {
char *result =NULL;
result =(char *)malloc(sizeof(char));
printf("you will check date to period,please enter date:\n");
int year,month,day;
scanf("%d,%d,%d",&year,&month,&day);
if((year<1940)||(year>2040))
{
printf("the year input is invalid,terminated.\n");
flag =false;
}
if((month<1)||(month>12))
{
printf("the month input is a invalid one,terminated.\n");
flag =false;
}
if((day<1)||(day>31))
{
printf("the day input is invalid,terminated.");
flag =false;
}
while (flag)
{
result =DateToPediod(year,month,day);
printf("the date %d %d %d is period %c.\n",year,month,day,*result);
break;
}
free (result);
break;
 }