析构函数有一点不理解
程序代码：stock.c:
#include "stdafx.h"
#include "stock.h"
#include <iostream>
Stock::Stock()
{
std::cout<<"Default constructor called\n";
company="no name";
shares=0;
share_val=0.0;
total_val=0.0;
}
Stock::Stock(const std::string &co,long n,double pr)
{
std::cout <<"Constructor using"<<co<<"called\n";
company=co;
shares=n;
share_val=pr;
set_tot();
}
Stock::~Stock()
{
std::cout<<"bye,"<<company<<"!\n";
}
void Stock::buy(long num,double price)
{
shares+=num;
share_val=price;
set_tot();
}
void Stock::sell(long num,double price)
{
shares-=num;
share_val=price;
set_tot();
}
void Stock::update(double price)
{
share_val=price;
set_tot();
}
void Stock::show()
{
using std::cout;
using std::ios_base;
ios_base::fmtflags orig=cout.setf(ios_base::fixed,ios_base::floatfield);
std::streamsize prec =cout.precision(3);
cout<<"Company: "<<company
<<" Shares: "<<shares<<'\n';
cout<<" Share price:$"<<total_val<<'\n';
cout.precision(2);
cout<<" Total Worth:$"<<total_val<<'\n';
cout.setf(orig,ios_base::floatfield);
cout.precision(prec);
}
stock.h:
#ifndef STOCK_H
#define STOCK_H
#include <string>
class Stock
{
public:
Stock();
Stock(const std::string &co,long n=0,double pr=0.0);
~Stock();
void buy(long num,double price);
void sell(long num,double price);
void update(double price);
void show();
private:
std::string company;
long shares;
double share_val;
double total_val;
void set_tot() {total_val=shares*share_val;}
};
#endif
main:
#include "stdafx.h"
#include <iostream>
#include "stock.h"
#include <stdio.h>
int main()
{
{
using std::cout;
cout<<"Using constructors to create new objects\n";
Stock stock1("Nanosmart",12,20.0);
stock1.show();
Stock stock2=Stock("Boffo Objects",2,2.0);
stock2.show();
cout<<"Assigning stock1 to stock2:\n";
stock2=stock1;
cout<<"Listing stock1 and stock2\n";
stock1.show();
stock2.show();
cout<<"Using a constructor to reset an object\n";
stock1=Stock("Nifty Foods",10,50.0);
cout<<"Revised stock1\n";
stock1.show();
cout<<"Done\n";
}
return 0;
}
结果：
程序代码：Using constructors to create new objects Constructor usingNanosmartcalled Company: Nanosmart Shares: 12 Share price:$240.000 Total Worth:$240.00 Constructor usingBoffo Objectscalled Company: Boffo Objects Shares: 2 Share price:$4.000 Total Worth:$4.00 Assigning stock1 to stock2: Listing stock1 and stock2 Company: Nanosmart Shares: 12 Share price:$240.000 Total Worth:$240.00 Company: Nanosmart Shares: 12 Share price:$240.000 Total Worth:$240.00 Using a constructor to reset an object Constructor usingNifty Foodscalled bye,Nifty Foods! Revised stock1 Company: Nifty Foods Shares: 10 Share price:$500.000 Total Worth:$500.00 Done bye,Nanosmart! bye,Nifty Foods! 请按任意键继续. . .
1：sotck2=stock1 这里传递的是数组的值还是数组的地址
2：stock1=Stock（"Nifty Foods"....）这一步为什么出现的是 Bye,Nifty Foods! 我理解应该是Bye,Nanosmart!
