请各位看一下这个是计算闰年的方法吗 2012为什么算不出

Question

#include <stdio.h>
int main()
{
    int a=0;
    printf("input a year:");
    scanf_s("%d", &a);
    if (a % 4 == 0)
    {
        
        if(a%100==0&&a%400==0)
            printf("%d in a leap year",a);
        else
            printf("%d in not a leap year", a);
    }
    else
    {
        printf("%d in not a leap year",a);
    }
}

Answer 1

if(a%100!=0 || a%400==0)