stocks2.cpp

C++&datastructure书籍源码,以前外教提供现在与大家共享

#include <iostream>
#include <fstream>
#include <string>
#include <iomanip>
using namespace std;

#include "tvector.h"
#include "strutils.h"  // for atoi and atof
#include "prompt.h"

struct Stock
{
    string symbol;
    string exchange;
    double price;
    int    shares;
    
    Stock()
     : symbol("dummy"),
       exchange("none"),
       price(0.0),
       shares(0)
    { }
    
    Stock(const string& n, const string& xc,
          double p, int ns)
     : symbol(n),
       exchange(xc),
       price(p),
       shares(ns)
    { }
};

class Portfolio
{
  public:
    Portfolio();
    void Read(const string& filesymbol);
    void Add(const Stock& s);
    
    void Print(ostream& out)                const;
    void Search(int lowPrice, Portfolio& p) const;
    int  Size()                             const;
     
  private:
    tvector<Stock> myStocks;
};

Portfolio::Portfolio()
  : myStocks(0)
{
    myStocks.reserve(20);   // start with room for 20 stocks
}

void Portfolio::Add(const Stock& s)
{
    int count = myStocks.size();  // # stocks before adding new one
    myStocks.push_back(s);        // vector size is updated
    int loc = count;
    
    // invariant: loc-1 is index of rightmost unprocessed stock
    //            for k in myStocks[loc+1..count], s < myStocks[s]
    
    while (0 < loc && s.symbol <= myStocks[loc-1].symbol)
    {   myStocks[loc] = myStocks[loc-1];
        loc--;
    }
    myStocks[loc] = s;
}  

void Portfolio::Read(const string& filesymbol)
{
    ifstream input(filesymbol.c_str());
    string symbol, exchange, price, shares;
    
    while (input >> symbol >> exchange >> price >> shares)
    {    //myStocks.push_back(Stock(symbol,exchange,atof(price),atoi(shares)));
        Add(Stock(symbol,exchange,atof(price),atoi(shares)));
    }
}

int Portfolio::Size() const
{
    return myStocks.size();
}

void Portfolio::Print(ostream& out) const
{
    int k;
    int len = myStocks.size();

	out.precision(3);        // show 3 decimal places
	out.setf(ios::fixed);    // for every stock price

    for(k=0; k < len; k++)
    {   out  << myStocks[k].symbol << "\t"
             << myStocks[k].exchange << "\t"
             << setw(8) << myStocks[k].price << "\t"
             << setw(12) << myStocks[k].shares << endl;
    }
}

void Portfolio::Search(int lowPrice, Portfolio& p) const
// postcondition: make p a portfolio of all the stocks that cost more than lowPrice
{
    int k;
    int len = myStocks.size();
    for(k=0; k < len; k++)
    {    if (myStocks[k].price > lowPrice)
         {  p.Add(myStocks[k]);
         }
    }
}

int main()
{
    string filesymbol = PromptString("stock file ");
    Portfolio port;
    Portfolio costly;
    
    port.Read(filesymbol);
    port.Print(cout);
    cout << endl << "----" << endl << "# stocks: " << port.Size() << endl;
    
    int low = PromptRange("enter low price ",2,300);
    port.Search(low,costly);
    
    costly.Print(cout);
    cout << "# matches = " << costly.Size() << endl;
    
    return 0;
}