geeksforgeeks-065-重载数组索引操作符

#include<iostream>
#include<cstdlib>
 
using namespace std;
 
// A class to represent an integer array
class Array
{
private:
    int *ptr;
    int size;
public:
    Array(int *, int);
 
    // Overloading [] operator to access elements in array style
    int &operator[] (int);
 
    // Utility function to print contents
    void () const;
};
 
 
// Implementation of [] operator.  This function must return a
// refernce as array element can be put on left side
int &Array::operator[](int index)
{
    if (index >= size)
    {
        cout << "Array index out of bound, exiting";
        exit(0);
    }
    return ptr[index];
}
 
// constructor for array class
Array::Array(int *p = NULL, int s = 0)
{
    size = s;
    ptr = NULL;
    if (s != 0)
    {
        ptr = new int[s];
        for (int i = 0; i < s; i++)
            ptr[i] = p[i];
    }
}
 
void Array::print() const
{
    for(int i = 0; i < size; i++)
        cout<<ptr[i]<<" ";
    cout<<endl;
}
 
// Driver program to test above methods
int main()
{
    int a[] = {1, 2, 4, 5};
    Array arr1(a, 4);
    arr1[2] = 6;
    arr1.print();
    arr1[8] = 6;
    return 0;
}

1 2 6 5
Array index out of bound, exiting