Problem about overload operator ++

This is a program just for testing operator overloading. But I found
the operator ++ doesn't act like on built-in types. For detail:
When
    int array[10];
    Ptr_to_T<int> smart_ptr(&array[0], array, 10);
    *smart_ptr++ = 10; // I want to modify array[0],but this sentence
modifies array[1]

Do I make myself clear?
Could some body tell me how to fix it ?

#include <iostream>
using namespace std;
template<typename T>
class Ptr_to_T
{
public:
    Ptr_to_T(T* p, T* array, int size):_p(p),_array(array),_size(size)
{}
    Ptr_to_T(T* p):_p(p){}
    Ptr_to_T& operator++(){//prefix
        _p += 1;
        return *this;
    }
    Ptr_to_T& operator++(int){//postfix
        cout << "Entering Operator++" << endl;
        T* temp = _p;
        _p += 1;
        return *this;
    }
    T& operator*(){
        cout << "Entering Operator*" << endl;
        return *_p;
    }
private:
    T* _p;
    T* _array;
    int _size;
};
int main()
{
    int array[10];
    Ptr_to_T<int> smart_ptr(&array[0], array, 10);
    *smart_ptr++ = 10;
    cout << array[0] << endl;
    cout << array[1] << endl;
}

Result:

Entering Operator++
Entering Operator*
4246640
10