判断年 月的值

int time::daysinMonth(int year, int month)
{
if(month < 1 || month > 12)
{
return -1;
}
bool leapYear = false;
if( (year%4==0 && year%100!=0) || (year%400==0))
{
leapYear = true;
}
switch(month)
{
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12:
{
return 31;
}
case 2:
{
if(leapYear)
{
return 29;
}
return 28;
}
case 4:
case 6:
case 9:
case 11:
{
return 30;
}
default:
break;
}
return -1;
}