为什么在oj上会运行时错误

#include
#include
using namespace std;
template
class douhao
{
public:
int n;
T* b = new T[n];
douhao(int N)
{
n = N;
}
};
int main()
{
char a[51];
int n;
while (cin >> a >> n)
{
douhao d(n);
for (int i = 0; i < n; i++)
{
cin >> d.b[i];
}
for (int i = 0; i < strlen(a); i++)
{
cout << a[i] << ",";
}
cout << endl;
for (int i = 0; i < n; i++)
{
cout << d.b[i] << ",";
}
cout << endl;
}
}

看oj报错信息和要求即可