1.
cow.h
#ifndef COW_H
#define COW_H
class Cow{
char name[20];
char * hobby;
double weight;
public:
Cow();
Cow(const char * nm, const char * ho, double wt);
Cow(const Cow & c);
~Cow();
Cow &operator=(const Cow & c);
void Showcow() const;
};
#endif
cow.cpp
#include "cow.h"
#include <iostream>
using namespace std;
#include <cstring>
Cow::Cow()
{
strcpy_s(name, 20, "new cow");
hobby = new char[4];
strcpy_s(hobby, 4, "cow");
weight = 0.0;
}
Cow::Cow(const char *nm, const char *ho, double wt)
{
weight = wt;
hobby = new char[strlen(ho) + 1];
strcpy_s(hobby, strlen(ho) + 1, ho);
strcpy_s(name, 20, nm);
}
Cow::Cow(const Cow &c)
{
strcpy_s(name, 20, c.name);
hobby = new char[strlen(c.hobby) + 1];;
strcpy_s(hobby, strlen(c.hobby) + 1, c.hobby);
weight = c.weight;
}
Cow::~Cow()
{
delete [] hobby;
}
Cow & Cow::operator=(const Cow & c)
{
delete [] hobby;
hobby = new char[strlen(c.hobby) + 1];
strcpy_s(hobby, strlen(c.hobby) + 1, c.hobby);
weight = c.weight;
strcpy_s(name, 20, c.name);
return *this;
}
void Cow::Showcow() const
{
cout << "Now a new cow!\n";
cout << "The name is " << name << endl;
cout << "The hobby is " << hobby << endl;
cout << "The weight is " << weight << endl;
}
play.cpp
#include "cow.h"
#include <iostream>
using namespace std;
int main()
{
cout << "See cows!\n";
Cow c1;
c1.Showcow();
Cow c2("A", "aaaa", 111.111);
c2.Showcow();
Cow c3("B", "bbbb", 222.222);
c3.Showcow();
c3 = c1;
Cow c4(c2);
c3.Showcow();
c4.Showcow();
return 0;
}
2.暫
3.
stock20.h
//改自清單10.7
#ifndef STOCK20_H
#define STOCK20_H
#include <iostream>
using namespace std;
class Stock{
char * company;//要求用動態內存分配代替string類對象，所以string對象company必須改爲char *類型
int shares;
double share_val;
double total_val;
void set_tot() {total_val = shares * share_val};
public:
Stock();
Stock(const char * 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);
friend ostream & operator<<(ostream &os, const Stock &st);//要求用重載的operator<<()定義代替show()成員函數
const Stock & topval(const Stock & s) const;
};
#endif
stock20.cpp
//改自清單10.8
#include "stock20.h"
#include <iostream>
using namespace std;
Stock::Stock()
{
company = new char[strlen("no name") + 1];
strcpy_s(company, strlen("no name") + 1, "no name");//對應string下的company="no name"
shares = 0;
share_val = 0.0;
total_val = 0.0;
}
Stock::Stock(const char *co, long n, double pr)
{
company = new char [strlen(co) + 1];
strcpy_s(company, strlen(co) + 1, co);
if(n < 0)
{
cout << "Number of shares can't be negative; "
<< company << " sahres set to 0.\n";
shares = 0;
}
else
shares = n;
share_val = pr;
set_tot();
}
Stock::~Stock()
{
delete [] company;
}
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();
}
}
void Stock::sell(long num, double price)
{
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();
}
ostream & operator<<(ostream &os, const Stock &st)
{
ios_base::fmtflags orig = cout.setf(ios_base::fixed, ios_base::floatfield);
streamsize prec = cout.precision(3);
cout << "Company: " << st.company << " Shares: " << st.shares << endl;
cout << " Share Price: $" << st.share_val;
cout.precision(2);
cout << " Total Worth: $" << st.total_val << endl;
cout.setf(orig, ios_base::floatfield);
cout.precision(prec);
return os;
}
const Stock & Stock::topval(const Stock & s) const
{
if(s.total_val > total_val)
return s;
else
return *this;
}
play.cpp
//清單10.9
#include <iostream>
#include "stock20.h"
const int STKS = 4;
int main()
{
Stock stocks[STKS] = {
Stock("NanoSmart", 12, 20.0),
Stock("Boffo Objects", 200, 2.0),
Stock("Monolithic Obelisks", 130, 3.25),
Stock("Fleep Enterprises", 60, 6.5)
};
cout << "Stock holdings:\n";
int st;
for(st = 0; st < STKS; st++)
cout << stocks[st];
const Stock * top = &stocks[0];
for(st = 1; st < STKS; st++)
top = &top->topval(stocks[st]);
cout << "\nMost valuable holding:\n";
cout << *top;
return 0;
}
4.暫
5.
queue.h
//清單12.10
#ifndef QUEUE_H
#define QUEUE_H
class Customer{
long arrive;
int processtime;
public:
Customer() {arrive = processtime = 0;}
void set(long when);
long when() const { return arrive;}
int ptime() const { return processtime;}
};
typedef Customer Item;
class Queue{
struct Node{
Item item;
struct Node * next;
};
enum {Q_SIZE = 10};
Node * front;
Node * rear;
int items;
const int qsize;
Queue(const Queue & q) : qsize(0) {}
Queue &operator=(const Queue & q) { return *this;}
public:
Queue(int qs = Q_SIZE);
~Queue();
bool isempty() const ;
bool isfull() const ;
int queuecount() const ;
bool enqueque(const Item &item);
bool dequeue(Item &item);
};
#endif
queue.cpp
//清單12.11
#include "queue.h"
#include <iostream>
using namespace std;
#include <cstdlib>
Queue::Queue(int qs) : qsize(qs)
{
front = rear = NULL;
items = 0;
}
Queue::~Queue()
{
Node * temp;
while (front != NULL)
{
temp = front;
front = front->next;
delete temp;
}
}
bool Queue::isempty() const
{
return items == 0;
}
bool Queue::isfull() const
{
return items == qsize;
}
int Queue::queuecount() const
{
return items;
}
bool Queue::enqueque(const Item & item)
{
if(isfull())
return false;
Node * add = new Node;
add->item = item;
add->next = NULL;
items ++;
if(front == NULL)
front = add;
else
rear->next = add;
rear = add;
return true;
}
bool Queue::dequeue(Item & item)
{
if(front == NULL)
return false;
item = front->item;
items--;
Node * temp = front;
front = front->next;
delete temp;
if(items == 0)
rear = NULL;
return true;
}
void Customer::set(long when)
{
processtime = rand() % 3 + 1;
arrive = when;
}
play.cpp
//改自清單12.12
#include <iostream>
#include "queue.h"
using namespace std;
#include <ctime>
#include <cstdlib>
const int MIN_PER_HR = 60;
bool newcustomer(double x);
int main()
{
srand(time(0));
cout << "Case Study: Bank of Heather Automatic Teller\n";
cout << "Enter maximum size of queue: ";
int qs;
cin >> qs;
Queue line(qs);
cout << "The simulation hour: 100" << endl;
int hours = 100;
long cyclelimit = MIN_PER_HR * hours;
double perhour;
double min_per_cust;
perhour = 1;
Item temp;
long turnaways = 0;
long customers = 0;
long served = 0;
long sum_line = 0;
int wait_time = 0;
long line_wait = 0;
double avetime = 0;
while (perhour++ && avetime<= 1)
{
while (!line.isempty())
line.dequeue(temp);
min_per_cust = MIN_PER_HR / perhour;
for(int cycle=0; cycle < cyclelimit; cycle++)
{
if(newcustomer(min_per_cust))
{
if(line.isfull())
turnaways++;
else
{
customers++;
temp.set(cycle);
line.enqueque(temp);
}
}
if(wait_time <= 0 && !line.isempty())
{
line.dequeue(temp);
wait_time = temp.ptime();
line_wait += cycle - temp.when();
served++ ;
}
if(wait_time > 0)
wait_time--;
sum_line += line.queuecount();
}
if(customers > 0)
{
cout << "customers accepted: " << customers << endl;
cout << " customers served: " << served << endl;
cout << " turnaways: " << turnaways << endl;
cout << "average queue size: ";
cout.precision(2);
cout.setf(ios_base::fixed, ios_base::floatfield);
cout << (double) sum_line / cyclelimit << endl;
cout << " average wait time: " << (double) line_wait / served << " minutes\n";
}
else
cout << "No customers!\n";
avetime = (double)line_wait / served;
}
cout << "When there comes " << perhour << " people per hour, the average wait time will be about 1 minute.\n";
cout << "Done!\n";
return 0;
}
bool newcustomer(double x)
{
return (rand() * x / RAND_MAX < 1);
}
6.
本題要求多開設一個ATM，所以我們就會有兩個隊列，一起進行服務，客戶到達之後的排隊方式即是，如果第一臺人數少於第二臺，則排第一隊，否則排第二隊。所以相比第5題，頭文件和實現文件依然不變，因爲本質性功能依然沒變，只需更改檢驗文件。
play.cpp
//改自清單12.12
#include <iostream>
#include "queue.h"
using namespace std;
#include <ctime>
#include <cstdlib>
const int MIN_PER_HR = 60;
bool newcustomer(double x);
int main()
{
srand(time(0));
cout << "Case Study: Bank of Heather Automatic Teller\n";
cout << "Enter maximum size of queue: ";
int qs;
cin >> qs;
Queue line1(qs);
Queue line2(qs);
cout << "The simulation hour: 100" << endl;
int hours = 100;
long cyclelimit = MIN_PER_HR * hours;
double perhour;
double min_per_cust;
perhour = 1;
Item temp;
long turnaways = 0;
long customers = 0;
long served = 0;
long sum_line = 0;
int wait_time1 = 0;
int wait_time2 = 0;
int line1_size = 0;
int line2_size = 0;
long line_wait = 0;
double avetime = 0;
while (perhour++ && avetime<= 1)
{
while (!line1.isempty())
line1.dequeue(temp);
while (!line2.isempty())
line2.dequeue(temp);
min_per_cust = MIN_PER_HR / perhour;
for(int cycle=0; cycle < cyclelimit; cycle++)
{
if(newcustomer(min_per_cust))
{
if(line1.isfull() && line2.isfull())
turnaways++;
else if (line1_size < line2_size)
{
customers++;
temp.set(cycle);
line1.enqueque(temp);
line1_size++;
}
else
{
customers++;
temp.set(cycle);
line2.enqueque(temp);
line2_size++;
}
}
if(wait_time1 <= 0 && !line1.isempty())
{
line1.dequeue(temp);
line1_size--;
wait_time1 = temp.ptime();
line_wait += cycle - temp.when();
served++ ;
}
if(wait_time2 <= 0 && !line2.isempty())
{
line2.dequeue(temp);
line2_size--;
wait_time2 = temp.ptime();
line_wait += cycle - temp.when();
served++ ;
}
if(wait_time1 > 0)
wait_time1--;
if(wait_time2 > 0)
wait_time2--;
sum_line += line1.queuecount();
sum_line += line2.queuecount();
}
if(customers > 0)
{
cout << "customers accepted: " << customers << endl;
cout << " customers served: " << served << endl;
cout << " turnaways: " << turnaways << endl;
cout << "average queue size: ";
cout.precision(2);
cout.setf(ios_base::fixed, ios_base::floatfield);
cout << (double) sum_line / cyclelimit << endl;
cout << " average wait time: " << (double) line_wait / served << " minutes\n";
}
else
cout << "No customers!\n";
avetime = (double)line_wait / served;
}
cout << "When there comes " << perhour << " people per hour, the average wait time will be about 1 minute.\n";
cout << "Done!\n";
return 0;
}
bool newcustomer(double x)
{
return (rand() * x / RAND_MAX < 1);
}
從結果上可以看出，當只有1臺ATM時，每小時到達客戶數爲25時，平均等候時間爲1分鐘，而兩臺ATM時，每小時到達客戶數爲60，平均等候時間爲1分鐘，所以效果不止翻倍。