c – 析构函数和解除分配的函数有什么区别？

我不明白他们对我来说看起来是一回事.他们做同样的事情,为什么你需要像DeAllocate这样的功能？析构函数具有自动调用的优点,但DeAllocate不会.

#include <iostream>
using namespace std;

const int SIZE=5;

class ARRAY_CLASS
{
public:
    ARRAY_CLASS();//default constructor
    ~ARRAY_CLASS(); //destructor
    void Add(int); //mutator
    void Print(); //accessor
    int * Get_Address(); //accessor
    void DeAllocate(); //mutator
private:

    int *A;
    int count;
};

ARRAY_CLASS::ARRAY_CLASS()
{
    cout<<"Default constructor has been calledn";
    A = new int[SIZE];
    count = 0;
}


ARRAY_CLASS::~ARRAY_CLASS()
{
    cout<<"The Destructor has been Called!n";
    delete [ ] A;
    A=0;
    count = 0;
}

void ARRAY_CLASS::Add(int item)
{
    if (count<SIZE)
        A[count++]=item;
    else
        cout<<"Array Fulln";
}
void ARRAY_CLASS::Print()
{
    for(int i=0; i<count; i++)
        cout<<"A[i] = "<<A[i]<<endl;
}

int * ARRAY_CLASS::Get_Address()
{
    return A;
}

void ARRAY_CLASS::DeAllocate()
{
    delete [ ] A;
    A = 0;
    count = 0;
}

int main()
{

    ARRAY_CLASS B;

    B.Add(1);
    B.Add(2);
    B.Add(3);
    B.Add(4);
    B.Add(5);

    B.Print();

    ARRAY_CLASS A = B;

    cout<<"A holds address location = "<<A.Get_Address()
    <<" and B holds address location "<<B.Get_Address()<<endl;

    B.DeAllocate();
    A.Print();

    return 0;
}