请问这个代码哪里有错误？

#include <stdio.h>
int main()
{
    int year = 2008;
    int month = 8;
    int day = 8;
    int sum,flag;
    switch(month)
    {
        case 1:sum=0;
        break;
        case 2:sum=31;
        break;
        case 3:sum=50;
        break;
        case 4:sum=81;
        break;
        case 5:sum=111;
        break;
        case 6:sum=142;
        break;
        case 7:sum=172;
        break;
        case 8:sum=203;
        break;
        case 9:sum=243;
        break;
        case 10:sum=273;
        break;
        case 11:sum=304;
        break;
        case 12:sum=334;
        break;
        default:
        break;
    }
    sum=sum+day;
    if(year%4==0&&year%100!=0)
    flag=1;
    else
    flag=0;
    if(flag==1&&month>2);
    sum+=1;
    printf("%d年%d月%d日是第%d天"，year,month,day,sum);
    return 0;
}