拷贝赋值实现

#include <iostream>
#include <cstring>

using namespace std;

//字符串赋值
char * mcopy(char *desc, const char *source)
{
    if (desc != NULL)
    {
        while (*source)
        {
            *desc++ = *source++;
        }
        *desc = '\0';
        return desc;
    }
    return NULL;
}

template<class T>
class A
{
private:
    T pt;
public:
    A(T t) :pt(t){}
    virtual ~A(){ }
    T getData() const{ return pt; }
    A& operator =(const A &ra);

};

//模板特化
template<>
class A<char *>
{
private:
    char* pt;
public:
    A(char* t) :pt(t){}
    virtual ~A(){ if (pt) delete []pt; }

    char* getData() const{ return pt; }
    A& operator =(const A &ra);

};

template<class T>
A<T>& A<T>::operator = (const A<T> &ra)
{
    T *npt = new T(ra.pt);
    pt = *npt;
    delete npt;
    return *this;
}

//特化 方法2实现
A<char *>& A<char *>::operator = (const A<char *> &ra)
{   
    pt = new char[strlen(ra.pt) + 1];
    mcopy(pt, ra.pt);

    return *this;
}

int main()
{
    A<int> ia(10);
    A<int> ib(12);
    ib = ia;
    cout << ib.getData() << endl;


    /*char a[] = "abc";
    char b[] = "de";*/
    char *a = "acb";
    char * b = "ddcd";

    A<char *> pA(a);
    A<char *> pB(b);
    pB = pA;
    cout << pB.getData() << endl;


    return 0;
}