days

/*储存12个月的天数*/const int days[12]={31,28,31,30,31,30,31,31,30,31,30,31};/*判断是否为闰年*/int isLeapYear(int year){ if(((year%4==0)&&(year%100!=0))    ||(year%400==0)) {  return 1; } return 0;}int CalcHowManyDays(unsigned int Year,                    unsigned int Month,                    unsigned int Day,                    unsigned int * pSumOfDays){    if(Month<=0||Month>12 || Day<=0||Day >31 || NULL == pSumOfDays)      return -1;    long sum=0;    int i;    //累计当年以往各月的天数    for(i=0;i<Month-1;i++)    {        sum+=days[i];    }    if(Month>2)    {        if(isLeapYear(Year))        {//闰年多一天            sum+=1;        }    }    //累计当年当月的天数    sum+=Day;    *pSumOfDays = sum;    return 0;}