Day before and after

#include<conio.h>
#include<stdio.h>
int main()
{
    int day, month, year, x, a[]={0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
    int day_after, month_after, year_after;
    printf("Enter (dd/mm/yy): ");
    scanf("%2d %2d %4d", &day, &month, &year);

    if (month== 2)
        if((year%400==0) || ((year%4==0) & (year%100!=0)))
            a[2] = 29;

    day_after = day;
    month_after = month;
    year_after = year;

     //Before
     if(day==1){
        month--;
        if(month<1){
            month=12;
            year--;
        }
        day = a[month];
     }else{
        day--;
     }
     //After
     if(day_after==a[month_after]){
        day_after = 1;
        month_after++;
        if(month_after>12){
            month_after=1;
            year_after++;
         }
    }else{
        day_after++;
     }
     printf("Before: %02d - %02d - %02d\n",day,month,year);
     printf("After:  %02d - %02d - %02d\n",day_after,month_after,year_after);
     getch();
}