int sum = 0;
int k = 0;
Console.WriteLine("请输入20个数:");
for (int i = 0; i <20; i++)
{
string s = Console.ReadLine();
int x = int.Parse(s);
if(x>0)
{
k++;
sum += x;
}
}
Console.WriteLine("正数:"+ k);
Console.WriteLine("和:" + sum);