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=59;break;

    case 4:sum=90;break;

    case 5:sum=120;break;

    case 6:sum=151;break;

    case 7:sum=181;break;

    case 8:sum=212;break;

    case 9:sum=243;break;

    case 10:sum=273;break;

    case 11:sum=304;break;

    case 12:sum=334;break;

    sum = sum + day;

    {

    if(year%400 == 0)

        flag=1;

    else

        flag=0;

    if(flag==1&&month>2)

        sum += 1;

    printf("%d年%d月%d日是该年的第%d天",year,month,day,sum);

    return 0;

}