一个简易式的c++交互程序（简易股票系统）

勿喷，虽然我自己也知道这很智障。。。。

stock类

//
// Created by lenovo on 2018/3/18.
//

#ifndef STOCK_STOCK10_H
#define STOCK_STOCK10_H

#include <string>
class stock{
private:
    std::string company;
    int shares;
    double share_val;
    double total_val;
    void set_tot(){total_val=shares*share_val;}
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()const;
    const stock &topval(const stock &s)const;
};

#endif //STOCK_STOCK10_H

简单定义一下吧，哈哈

//
// Created by lenovo on 2018/3/18.
//

#include <iostream>
#include "stock10.h"

stock::stock() {
    company="no name";
    shares=0;
    share_val=0.0;
    total_val=0.0;
}

stock::stock(const std::string &co, long n, double pr) {
    company=co;
    if(n<0){
        std::cout<<"Number of shares can't be negative;"
                 <<company<<" shares set to 0\n";
        shares=0;
    }
    else
        shares=n;
    share_val=pr;
    set_tot();
}

stock::~stock() {
    std::cout<<"Bye!";
}

void stock::buy(long num, double price) {
    if(num<0){
        std::cout<<"Number of shares purchased can't be negative."
                 <<"Transaction is aborted.\n";
    }
    else{
        shares+=num;
        share_val=price;
        set_tot();
    }
}

void stock::sell(long num, double price) {
    using std::cout;
    if(num<0){
        cout<<"Number of shares sold can'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() const {
    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<<"shares price: $"<<share_val;
    cout.precision(2);
    cout<<"   Total worth is $"<<total_val<<"\n";
    cout.setf(orig,ios_base::floatfield);
    cout.precision(prec);
}

const stock&stock::topval(const stock &s) const {
    if(s.total_val>total_val)
        return s;
    else
        return *this;

}

再写一个蠢到爆的cpp

#include <iostream>
#include "stock10.h"

const int size=4;
int main()
{
    using namespace std;
    stock stocks[size]={
            stock("Nanosmart",12,20.0),
            stock("Boffo objects",200,2.0),
            stock("Monolithic obelisks",130,3.25),
            stock("Fleep Enterprise",60,6.5)
    };

    cout<<"stock holding:\n";
    int st;
    for (int st = 0; st <size ; st++) {
        stocks[st].show();
    }
    const stock*top=&stocks[0];
    for (int st = 0; st <size ; st++) {
        top=&top->topval(stocks[st]);
    }
    cout<<"The most valuable holding :\n";
    top->show();

    return 0;
}