2020/3/4

Network + course work: 5 hours

cf: 2 Xiaoshi

Knowledge Learning Tree Hash: 1 hour

English words: 1 hour

Recalling c ++ Chapter 10: 1 hour

#include "the iostream" 
#include "CString" 

class Stock 
{ 
Private: 
    char Company [30]; 
    int shares; 
    Double share_val; 
    Double Total_val; 
    void set_tot () {/// The class declaration is often short member functions as inline 
        * = shares share_val Total_val; 
    } 
public: /// function defined in the class declaration are automatically inline function 
    Stock (); 
    Stock (CO.'s const char *, int n-, Double PR); /// constructor 
    ~ Stock (); /// destructor 
    void Buy (int NUM, Double. price); 
    void Sell (int NUM, Double. price); 
    void Update (Double. price); 
    void Show (); 
    const & TopVal Stock (const & Stock S) const; 
};

Stock :: Stock(const char * co,int n,double pr)
{
   // std::cout << "Constructor using "　;
    std::strncpy(company,co,29);
    company[29] = '\0';
    if(n < 0)
    {
        std :: cerr << "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 <<" Default constructor called\n";
    std :: strcpy(company,"no name");
    shares = 0;
    share_val = 0.0;
    total_val = 0.0;
}
Stock :: ~Stock()
{
    std :: cout << "Bye, " << company << "!\n";
}
void Stock :: buy(int num,double price)
{
    if(num < 0)
    {
        std:: cerr<<"Number of shares purchased can't be negative. "
        << "Transaction is aborted.\n";
    }
    else {
       shares += num;
       share_val = price;
       set_tot();
    }
}
void Stock::sell(int num,double price)
{
    using std::cerr;
    if(num < 0)
    {
        cerr << "Number of shares sold can't be negative."
        << "Transaction is aborted.\n";
    } else if(num > shares)
    {
        cerr << "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()
{
    using std :: cout;
    using std :: endl;
    cout << "Company: " << company << " Shares: "
    << shares << endl <<" Share Price: $" << share_val
    << " Total Worth: $" << total_val << endl;
}
const Stock & Stock :: topval(const Stock & s)const
{
    if(s.total_val > total_val) return s;
    else return *this;
}
int main()
{
    using std :: cout;
    using std :: ios_base;
    cout.precision(2);
    cout.setf(ios_base :: fixed,ios_base :: floatfield);
    cout.setf(ios_base::showpoint);

    cout << "Using constructors to create new objects\n";
    Stock stock1("NanoSmark",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 ans stock2: \n";
    stock1.show (); 
    stock2.show();
    cout << "Using a constructor to reset an object\n";
    stock1 = Stock ( "Nofty Foods", 10,50.0); /// attention here, because there is a value of the stock1 
    /// so here stock1 not call the constructor again, but there is a assigned to anonymous objects 
    /// stock1, after the assignment is completed, the implementation of the anonymous objects destructor 
    COUT << "Revised stock1: \ n-"; 
    stock1.show (); 
    COUT << "the Done \ n-"; 

    const = Stock Land Stock ( "Kludgehorn the Properties"); 
    //land.show();/// Note this statement to be wrong, because there is no guarantee, show function, no land to change 
    /// unless defined time show () function definition is: void show () const; function does not modify the call object to ensure 

    return 0; 
}