#include <stdio.h>

int main() 

{ 

    /* 定义需要计算的日期 */

    int year = 2008;

    int month = 8;

    int day = 8;

    int m;

    int sum=0;

    if(year%4==0&&year%100!=0||year%400==0)   //这行的两个符号你的程序里是错的

        m=29;

        else

        m=28;

        switch(month)

    {

        case 1: sum=0;break;

        case 2: sum=31;break;

        case 3: sum=m+31;break;

        case 4: sum=m+31+31;break;

        case 5: sum=m+31+31+30;break;

        case 6: sum=m+31+31+30+31;break;

        case 7: sum=m+31+31+30+31+30;break;

        case 8: sum=m+31+31+30+31+30+31;break;

        case 9: sum=m+31+31+30+31+30+31+31;break;

        case 10: sum=m+31+31+30+31+30+31+31+30;break;

        case 11: sum=m+31+31+30+31+30+31+31+30+31;break;

        case 12: sum=m+31+31+30+31+30+31+31+30+31+30;break; 

        default:printf("您输入的月份有误！\n");break;

    }

    printf("2008年8月8日是该年的第%d天",sum+8);

    return 0;

}