使用指针储存,使用中括号重载进行输入和访问
注意内存释放要用delete[],而不是delete,因为释放的是数组空间

#include<iostream>
#include<iomanip>
using namespace std;

template<class T>
class Array
{
private:
    T* val;
    int size;
public:
    Array(int s = 10);
    ~Array();
    T getsum();
    T& operator[](int sub);
};

template<class T>
Array<T>::Array(int s) : size(s)
{
    val = new T[s];
}

template<class T>
Array<T>::~Array()
{
    delete[] val;
}

template<class T>
T Array<T>::getsum()
{
    T res = 0;
    for (int i = 0; i < size; i++) res += val[i];
    return res;
}

template<class T>
T& Array<T>::operator[](int sub)
{
    return val[sub];
}

int main()
{
    int i, n, m;
    cin >> n >> m;
    Array<int> a1(n);
    Array<double> a2(m);
    for (i = 0; i < n; i++) cin >> a1[i];
    for (i = 0; i < m; i++) cin >> a2[i];
    cout << a1.getsum() << endl;
    cout << fixed << setprecision(2) << a2.getsum();
}