《C++语言基础》程序阅读——构造函数和析构函数

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请写出下面程序的运行结果，再和计算机运行的结果对照。无论对错，再想一想。

#include <iostream>
using namespace std;
class A
{
    int a , b ;
public :
    A( ) 
    {
        a=b=0;
        cout <<"a="<<a<<","<<"b="<<b<<endl;
    }
    A(int aa, int bb): a(aa),b(bb)
    {
        cout <<"a="<<a<<","<<"b="<<b<<endl;
    }
    ~A( )
    {
        cout<<"Destructor "<<a<<" "<<b<<endl;
    }
};
int main()
{
    A x, y(2, 3);
    return 0;
}

#include <iostream>
using namespace std;
class A
{
public:
    A()
    {
        cout<<"A";
    }
    ~A()
    {
        cout<<"~A";
    }
};
class B
{
    A *p;
public:
    B()
    {
        cout<<"B";
        p=new A();
    }
    ~B()
    {
        cout<<"~B";
        delete p;
    }
};
int main()
{
    B obj;
    return 0;
}

#include <iostream>
using namespace std;
class toy
{
public:
    toy(int q, int p)
    {
        quan = q;
        price = p;
    }
    int get_quan()
    {
        return quan;
    }
    int get_price()
    {
        return price;
    }
private:
    int quan, price;
};
int main()
{
    toy op[3][2]=
    {
        toy(10,20),toy(30,48),
        toy(50,68),toy(70,80),
        toy(90,16),toy(11,120)
    };
    int i;
    for (i=0; i<3; i++)
    {
        cout<<op[i][0].get_quan()<<",";
        cout<<op[i][0].get_price()<<"\n";
        cout<<op[i][1].get_quan()<<",";
        cout<<op[i][1].get_price()<<"\n";
    }
    cout<<"\n";
    return 0;
}

#include <iostream>
using namespace std;
class DA
{
    int k;
public:
    DA(int x=1): k(x) { }
    ~DA()
    {
        cout<<k;
    }
};
int main()
{
    DA d[]= {DA(3),DA(3),DA(3) };
    DA *p=new DA[2];
    delete []p;
    return 0;
}