一个日期推算的程序

#include<stdio.h>
#define judge(y)  (y%4==0)&&(y%100!=0)||(y%400==0)
int allday(int x);
 int month1[]={31,28,31,30,31,30,31,31,30,31,30,31};
 int month2[]={31,29,31,30,31,30,31,31,30,31,30,31};

void main()
{ int i;
 
  int yea1,yea2,mon1,mon2,day1,day2;
  int *p;
 
  long jia_day1=0;
  long jia_day2=0;
  long jia_day3=0;
  long jia_day4=0;
  long jia_all=0;

  printf("请输入第一个年月份\n");
  scanf("%d %d %d",&yea1,&mon1,&day1);
  printf("请输入第二个年月份\n");
  scanf("%d %d %d",&yea2,&mon2,&day2);
  if(judge(yea1))  printf("%d是闰年\n",yea1);
  if(judge(yea2))  printf("%d是闰年\n",yea2);
if(yea1>yea2)  
{ if(judge(yea2)) p=month2;
      else p=month1;
       jia_day1=*(p+mon2-1)-day2;
          for(i=mon2;i<=11;i++)        
           jia_day2=jia_day2+*(p+i); 
          for(i=yea2+1;i<yea1;i++)
             jia_day3=jia_day3+allday(i);  
    if(judge(yea1)) p=month2;
    else p=month1;
       for(i=1;i<mon1;i++)
           jia_day4=jia_day4+*(p+i-1);
       jia_all=jia_day1+jia_day2+jia_day3+jia_day4+day1;
       printf("%d%d%d比%d%d%d迟%d天\n",yea1,mon1,day1,yea2,mon2,day2,jia_all);
   }
else if(yea1<yea2)
{ if(judge(yea1)) p=month2;
   else p=month1;
       jia_day1=*(p+mon1-1)-day1;
          for(i=mon1;i<=11;i++)        
           jia_day2=jia_day2+*(p+i); 
          for(i=yea1+1;i<yea2;i++)
             jia_day3=jia_day3+allday(i);  
     if(judge(yea2)) p=month2;
      else p=month1;
       for(i=1;i<mon2;i++)
           jia_day4=jia_day4+*(p+i-1);
       jia_all=jia_day1+jia_day2+jia_day3+jia_day4+day2;
       printf("%d%d%d比%d%d%d迟%d天\n",yea2,mon2,day2,yea1,mon1,day1,jia_all);
   }
else
{ if(judge(yea1)) p=month2;
   else p=month1;
   if(mon1>mon2)
   {  jia_day1=*(p+mon2-1)-day2;
    for(i=mon2+1;i<mon1;i++)
    jia_day2=jia_day2+*(p+i-1);
     jia_all=jia_day1+jia_day2+day1;
    printf("第一个时间比第二个时间迟%d天\n",jia_all);
    }
 else if(mon1<mon2)
 {   jia_day1=*(p+mon1-1)-day1;
  for(i=mon1+1;i<mon2;i++)
    jia_day2=jia_day2+*(p+i-1);
     jia_all=jia_day1+jia_day2+day2;
    printf("第一个时间比第二个时间早%d天\n",jia_all);
    }
 else
    {if(day1>day2)
        printf("第一个时间比第二个时间迟%d天\n",(day1-day2));
     else if(day1<day2)
        printf("第一个时间比第二个时间早%d天\n",(day2-day1)); 
      else printf("这俩个时间相等\n");
    }
 }
}

 
int allday(int x)
{ int y;
  if(((x%4==0)&&(x%100!=0))||((x%100==0)&&(x%400==0)))
  {y=366;  printf("在这俩个数据中:%d是闰年\n",x);}
 else y=365;
  return (y);
}