C++语言基础 例程 调用构造函数和析构函数的顺序

贺老师的教学链接  本课讲解

析构函数应用实例
方案1

const int N =500;
class Salary
{
public:
    Salary(int);
    void input( );
    void show( );
    ~Salary();
private:
    double salarys[N];
    int number; //实际人数
};

方案2

class Salary
{
public:
    Salary(int);
    void input( );
    void show( );
    ~Salary();
private:
    double *salarys;
    int number; //实际人数
};
Salary::Salary(int n)
{
    number = n;
    salarys=new double[number];
}
Salary::~Salary()
{
    delete []salarys;
}

谁先分配? 谁先释放？

#include <iostream>
using namespace std;
class Salary
{
public:
    Salary(int);
    void input( );
    void show( );
    ~Salary();
private:
    double *salarys;
    int number; //实际人数
};
Salary::Salary(int n)
{
    number = n;
    salarys=new double[number];  //分配大小正好合适的空间存放数据
}
Salary::~Salary()
{
    delete []salarys;
}
void Salary::input( )
{
    double x;
    int i;
    for(i=0; i<number; ++i)
    {
        cin>>x;
        salarys[i]=x;
    }
}

void Salary::show( )
{
    int i;
    for (i=0; i<number; i++)
        cout<<salarys[i]<<" ";
    cout<<endl;
}

int main( )
{
    Salary s1(50);
    s1.input( );
    Salary s2(1248);
    s2.input( );
    s1.show( );
    s2.show( );
    return 0;
}