为什么算的答案不对int year = 2008; int month = 8; int day = 8; int i; if(year%4==0&&year%100!=0 || year%400==0) i=1; else i=0; switch(month) { case 12: day += 30; case 11: day += 31; case 10: day

int year = 2008;

    int month = 8;

    int day = 8;

    int i;

    if(year%4==0&&year%100!=0 || year%400==0)

        i=1;

    else

        i=0;

    switch(month)

    {

        case 12: day += 30;

        case 11: day += 31;

        case 10: day += 30;

        case 9: day += 31;

        case 8: day += 31;

        case 7: day+= 30;

        case 6:day += 31;

        case 5: day += 30;

        case 4: day += 31;

        case 3: day == day+28+i;

        case 2: day += 31;

        break;

    }

    printf("%d年%d月8日是该年第%d天",year,month,day);

return 0;

}

为什么算的答案不对？