请教高手 c++编程问题

int comdays(int y,int m,int d)
{
bool runnian;
if(y % 4 == 0)
if(y % 100 == 0 && y % 400 !=0)
runnian = true;
int month[12] = {31,28,31,30,31,30,31,31,30,31,30,31};

int days = 0;
for(int i=0;i<m-1;i++)
days += month[i];

return runnian ? (days + d + 1):(days + d);
}

int comdays(int y, int m, int d)
{
int day,month,year,sum,leap;
day=d;
year=y;
month=m;
switch(month)/*先计算某月以前月份的总天数*/
{
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;
default:printf("data error");break;
}
sum=sum+day;/*再加上某天的天数*/
if(year%400==0||(year%4==0&&year%100!=0)