P10.3 usestock0.cpp

stock.h

#ifndef STOCK_H

#define STOCK_H

#include <string>

class Stock  //类声明

{

private:

    std::string company;

    long shares;  //

    double share_val;

    double total_val;

    void set_tot(){total_val=share_val*shares;}

public:

    void acquire(const std::string &co,long n,double pr);  //获得股票

    void buy(long num,double price);  //买入股票

    void sell(long num,double price);  //卖出股票

    void update(double price);  //更新股票价格

    void show();  //显示关于所持股票的信息

};

#endif // STOCK_H

main.cpp

#include <iostream>

#include "stock.h"

using namespace std;

//对某个公司股票的首次购买

void Stock::acquire(const string &co, long n, double pr)

{

    company=co;

    if(n<0)

    {

        cout<<"Number of shares can't be negative;"

           <<company<<"shares set to 0.\n";

    }

    else

    {

        shares=n;

    }

    share_val=pr;

    set_tot();

}

//购买股票

void Stock::buy(long num, double price)

{

    if(num<0)

    {

        cout<<"Number of shares purchased can't be negative."

           <<"Transaction is aborted.\n";

    }

    else

    {

        shares+=num;

        share_val=price;

        set_tot();

    }

}

//减少持有的股票

void Stock::sell(long num, double price)

{

    if(num<0)

    {

        cout<<"Number of shares sold cna't be negative."

           <<"Transaction is aborted.\n";

    }

    else if(num>shares)

    {

        cout<<"You can't sell more than you have!"

           <<"Transaction is aborted.\n";

    }

    else

    {

        shares-=num;

        share_val=price;

        set_tot();

    }

}

//

void Stock::update(double price)

{

   share_val=price;

   set_tot();

}

void Stock::show()

{

    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<<" Shares Price:$"<<share_val;

       cout.precision(3);

     cout<<" Total Worth:$"<<total_val<<'\n';

     //show()应重置格式信息，使其恢复到自己被调用前的状态

     cout.setf(orig,ios_base::floatfield);

     cout.precision(prec);

}

int main(int argc, char *argv[])

{

    cout << "Hello World!" << endl;

    Stock fluffy_the_cat;

    fluffy_the_cat.acquire("NanoSmart",20,12.50);

    fluffy_the_cat.show();

    fluffy_the_cat.buy(15,18.125);

    fluffy_the_cat.show();

    fluffy_the_cat.sell(400,20.00);

    fluffy_the_cat.show();

    fluffy_the_cat.buy(300000,40.125);

    fluffy_the_cat.show();

    fluffy_the_cat.sell(300000,0.125);

    fluffy_the_cat.show();

    return 0;

}

运行结果如下

巴特西

P10.3 usestock0.cpp

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