ช่วยดู C++ โปรแกรมอธิกวาร มันผิดตรง Int หาแค่ปีนะค่ะ

#include<conio.h>
#include <stdio.h>
main()
{
    int year,check1,check2,check3 ;     <<<ตรงนี้ขึ้นแดงค่ะ
    printf("\t\tProgram check 'Leap year'.\n");
    printf("\t\tInput 'yyyy' Only.\n");
    printf("\t\tInput:");
    scanf(" %d ",&year);
    check1=year%4;
    check2=year%400;
    check3=year0;
    if (check1==0){
        if(check3!=0){
                printf(" %d is a leap year.\n",year);
            }else if(check3==0&&check2==0){
                printf(" %d is a leap year.\n",year);
            }else{
            printf(" %d is not a leap year.\n",year);
            }
        }else{
        printf(" %d is not a leap year.\n",year);
    }
    }else{
        printf("\t\tData fail.!!!\n");
    }
    }
   return 0;
}