哪里错了.

#include <stdio.h>
int main()
{
    /* 定义需要计算的日期 */
    int year = 2008;
    int month = 8;
    int day = 8;
    int sum,flage;
    switch(month)
    {
        case 1:printf("sum=0");break;
        case 2:printf("sum=31");break;
        case 3:printf("sum=59");break;
        case 4:printf("sum=90");break;
        case 5:printf("sum=120");break;
        case 6:printf("sum=151");break;
        case 7:printf("sum=181");break;
        case 8:printf("sum=212");break;
        case 9:printf("sum=243");break;
        case 10:printf("sum=273");break;
        case 11:printf("sum=304");break;
        case 12:printf("sum=334");break;
    }
    sum+=day;
    if(year%4==0&&year%100!=0)
    {
        flage=1;
    }
    else
    {
        flage=0;
    }
    if(flage=1&&month>2)
    {
        sum++;
    }
    printf("%d年%d月%d日是第%d天",year,month,day,sum);