#include<stdio.h>
void main()
{
    int year,leap;
    scanf("%d",&year);
    if(year%4==0)
    {
        if(year%100==0)
        {
            if(year%400==0)
                [bo]leap=1;
            else
                leap=0;
        }
        else
            leap=1;
    }
    else
        leap=0;[/bo]    if(leap)
        printf("%d is",year);
    else
        printf("%d is not",year);
    printf(" a leap year.\n");
}
上面有颜色的字是我不懂的地方，我是初学者，请版主帮个忙帮我分析下。