C++ Primer Plus 12章源码

# C++ Primer Plus 第十二章书上源码

记录我看C++ Primer Plus(第六版)第十二章源代码

12.1

//12.1
#include
#ifndef STRNGBAD_H_
#define STRNGBAD_H_
class StringBad
{
    private:
        char *str;
        int len;
        static int num_strings;
    public:
        StringBad(const char *s);
        StringBad();
        ~StringBad();
        friend std::ostream &operator<<(std::ostream &os, const StringBad &st);
};
#endif

12.2

#include
#include"strngbad.h"
using std::cout;
int StringBad::num_strings = 0;
StringBad::StringBad(const char *s)
{
    len = std::strlen(s);
    str = new char[len + 1];
    std::strcpy(str, s);
    num_strings++;
    cout << num_strings << ": \"" << str << "\"object created\n";

}
StringBad::StringBad()
{
    len = 4;
    str = new char[4];
    std::strcpy(str, "C++");
    num_strings++;
    cout << num_strings << ": \"" << str << "\" default object created\n";
}
StringBad::~StringBad()
{
    cout << "\"" << str << "\" objecy deleted, ";
    --num_strings;
    cout << num_strings << " left\n";
    delete[] str;
}
std::ostream & operator<<(std::ostream &os, const StringBad &st)
{
    os << st.str;
    return os;
}

12.3

#include
using std::cout;
#include"strngbad.cpp"

void  callme1(StringBad &);
void callme2(StringBad);
int main()
{
    using std::endl;
    {
        cout << "Starting an inner bllock.\n";
        StringBad headline1("Celery Stalks at Midnight");
        StringBad headline2("Lettuce Prey");
        StringBad sports("Spinach Leaves Bow1 for Dollars");
        cout << "headline1: " << headline1 << endl;
        cout << "headline2: " << headline2 << endl;
        cout << "sports: " << sports << endl;
        callme1(headline1);
        cout << "headline1: " << headline1 << endl;
        callme2(headline2);
        cout << "headline2: " << headline2 << endl;
        cout << "Initialize one object to another:\n";
        StringBad sailor = sports;
        cout << "sailor: " << sailor << endl;
        cout << "Assign one object to another:\n";
        StringBad knot;
        knot = headline1;
        cout << "Knot: " << knot << endl;
        cout << "Exiting the block.\n";
       
    }
    cout << "End of main()\n";
    return 0;
}
void callme1(StringBad &rsb)
{
    cout << "String passed by reference:\n";
    cout << "  \"" << rsb << "\"\n";
}
void callme2(StringBad sb)
{
    cout << "String passed by value:\n";
    cout<<" \""<

12.4

//12.4
#ifndef STRING1_H_
#define STRING1_H_
#include
using std::ostream;
using std::istream;
class String
{
    private:
        char *str;
        int len;
        static int num_strings;
        static const int CINLIM = 80;
    public:
        String(const char *s);
        String();
        String(const String &);
        ~String();
        int length() const { return len; }
        String &operator=(const String &);
        String &operator=(const char *);
        char &operator[](int i);
        const char &operator[](int i) const;

        friend bool operator<(const String &st, const String &st2);
        friend bool operator>(const String &st1, const String &st2);
        friend bool operator==(const String &st, const String &st2);
        friend ostream &operator<<(ostream &os, const String &st);
        friend istream &operator>>(istream &is, String &st);

        static int HowMany();
};
#endif

12.5

//12.5
#include
#include"string1.h"
using std::cin;
using std::cout;
int String::num_strings = 0;
String::String(const char *s)
{
    len = std::strlen(s);
    str = new char[len + 1];
    std::strcpy(str, s);
    num_strings++;
}
String::String()
{
    len = 4;
    str = new char[1];
    str[0] = '\0';
    num_strings++;
}
String::String(const String &st)
{
    num_strings++;
    len=st.len;
    str = new char[len + 1];
    std::strcpy(str, st.str);
}
String::~String()
{
    --num_strings;
    delete[] str;
}
String &String::operator=(const String &st)
{
    if(this==&st)
        return *this;
    delete[] str;
    len = st.len;
    str = new char[len + 1];
    std::strcpy(str, st.str);
    return *this;
}
String &String::operator=(const char *s)
{
    delete[] str;
    len = std::strlen(s);
    str = new char[len + 1];
    std::strcpy(str, s);
    return *this;
}
char &String::operator[](int i)
{
    return str[i];
}
const char &String::operator[](int i) const
{
    return str[i];
}

bool operator<(const String &st1, const String &st2)
{
    return (std::strcmp(st1.str, st2.str) < 0);
}
bool operator>(const String &st1, const String &st2)
{
    return st2 > st1;
}
bool operator==(const String &st1, const String &st2)
{
    return (std::strcmp(st1.str, st2.str) == 0);
}
ostream &operator<<(ostream &os, const String &st)
{
    os << st.str;
    return os;
}
istream &operator>>(istream &is, String &st)
{
    char temp[String::CINLIM];
    is.get(temp, String::CINLIM);
    if(is)
        st = temp;
    while(is&&is.get()!='\n')
        continue;
    return is;
}

 int String::HowMany()
 {
     return num_strings;
 }

12.6

#include
#include"string1.cpp"
const int ArSize = 10;
const int MaxLen = 81;
int main()
{
    using std::cin;
    using std::cout;
    using std::endl;
    String name;
    cout << "Hi what's your name?\n>>";
    cin >> name;
    cout <:\n";
    String sayings[ArSize];
    char temp[MaxLen];
    int i;
    for (i = 0; i < ArSize;i++)
    {
        cout << i+1<< ": ";
        cin.get(temp, MaxLen);
        while(cin&&cin.get()!='\n')
            continue;
        if(!cin||temp[0]=='\0')
            break;
        else
            sayings[i] = temp;
    }
    int total = i;
    if(total>0)
    {
        cout << "Here are your sayings:\n";
        for (i = 0; i < total;i++)
            cout << sayings[i][0] << ": " << sayings[i] << endl;
        int shortest = 0;
        int first = 0;
        for (i = 1; i < total;i++)
        {
            if(sayings[i].length()

12.7

#include
#include
#include
#include"string1.cpp"
const int ArSize = 10;
const int MaxLen = 81;
int main()
{
    using namespace std;
    String name;
    cout << "Hi, what's your name?\n>>";
    cin >> name;
    cout << name << ", please enter up to " << ArSize
         << " short sayings :\n";
    String sayings[ArSize];
    char temp[MaxLen];
    int i;
    for (i = 0; i < ArSize;i++)
    {
        cout << i + 1 << ": ";
        cin.get(temp, MaxLen);
        while(cin&&cin.get()!='\n')
            continue;
        if(!cin||temp[0]=='\0')
            break;
        else
            sayings[i] = temp;
    }
    int total = i;
    if(total>0)
    {
        cout << "Here are your sayings:\n";
        for (i = 0; i < total;i++)
            cout << sayings[i] << "\n";
        String *shortest = &sayings[0];
        String *first = &sayings[0];
        for (i = 1; i < total;i++)
        {
            if(sayings[i].length()length())
                shortest = &sayings[i];
            if(sayings[i]<*first)
                first = &sayings[i];
            cout << "Shortest saying:\n"
                 << *shortest << endl;
            cout << "First alphabetically:\n"
                 << *first << endl;
            srand(time(0));
            int choice = rand() % total;
            String *favorite = new String(sayings[choice]);
            cout << "My favorite saying:\n"
                 << *favorite << endl;
            delete favorite;
        }
        

    }
    else 
            cout << "Not much to say,eh?\n";
    cout << "Bye.\n";
    return 0;

}

12.8

#include
#include
#include
using namespace std;
const int BUF = 512;
class JustTesting
{
    private:
        string words;
        int number;
    public:
        JustTesting(const string &s="Just Testing",int n=0)
        {
            words = s;
            number = n;
            cout << words << " constructed\n";
        }
        ~JustTesting()
        {
            cout << words << " destroyed\n";
        }
        void Show() const { cout << words << "," << number << endl; }
};
int main()
{
    char *buffer = new char[BUF];
    JustTesting *pc1, *pc2;
    pc1 = new (buffer) JustTesting;
    pc2 = new JustTesting("Heap1", 20);
    cout << "Meory block addresses:\n"
         << "Buffer: "
         << (void *)buffer << "     heap:" << pc2 << endl;
    cout << "Memory contents:\n";
    cout << pc1 << ": ";
    pc1->Show();
    cout << pc2 << ": ";
    pc2->Show();

    JustTesting *pc3, *pc4;
    pc3 = new (buffer) JustTesting("Bad Idea", 6);
    pc4 = new JustTesting("Heap2", 10);
    cout << "Memory contents:\n";
    cout << pc3 << ": ";
    pc3->Show();
    cout << pc4 << ": ";
    pc4->Show();
    delete pc2;
    delete pc4;
    delete[] buffer;
    cout << "Done\n";
    return 0;
}

12.9

#include
#include
#include
using namespace std;
const int BUF = 512;
class JustTesting
{
    private:
        string words;
        int number;
    public:
        JustTesting(const string &s="Just Testing",int n=0)
        {
            words = s;
            number = n;
            cout << words << " constructed\n";
        }
        ~JustTesting()
        {
            cout << words << " destroyed\n";
        }
        void Show() const { cout << words << "," << number << endl; }
};
int main()
{
    char *buffer = new char[BUF];
    JustTesting *pc1, *pc2;
    pc1 = new (buffer) JustTesting;
    pc2 = new JustTesting("Heap1", 20);
    cout << "Meory block addresses:\n"
         << "Buffer: "
         << (void *)buffer << "     heap:" << pc2 << endl;
    cout << "Memory contents:\n";
    cout << pc1 << ": ";
    pc1->Show();
    cout << pc2 << ": ";
    pc2->Show();

    JustTesting *pc3, *pc4;
    pc3 = new (buffer+sizeof(JustTesting)) JustTesting("Better Idea", 6);
    pc4 = new JustTesting("Heap2", 10);
    cout << "Memory contents:\n";
    cout << pc3 << ": ";
    pc3->Show();
    cout << pc4 << ": ";
    pc4->Show();
    delete pc2;
    delete pc4;
    pc3->~JustTesting();
    pc1->~JustTesting();
    delete[] buffer;
    cout << "Done\n";
    return 0;
}

12.10

//12.10
#ifndef QUEUE_H_
#define QUEUE_H_
class Customer
{
    private:
        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
{
    private:
        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 enqueue(const Item &item);
        bool dequeue(Item &item);
};
#endif

12.11

//12.11
#include"queue.h"
#include


        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::enqueue(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 = std::rand() % 3 + 1;
            arrive = when;
        }

12.12

#include
#include
#include
#include"queue.cpp"
const int MIN_PER_HR = 60;
bool newcustomer(double x);
int main()
{
    using std::cin;
    using std::cout;
    using std::endl;
    using std::ios_base;
    std::srand(std::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 << "Enter the number of simulation hours: ";
    int hours;
    cin >> hours;
    long cyclelimit = MIN_PER_HR * hours;
    cout << "Enter the average number of customers per hour: ";
    double perhour;
    cin >> perhour;
    double min_per_cust;
    min_per_cust = MIN_PER_HR;
    Item temp;
    long turnaways = 0;
    long customers = 0;
    long served = 0;
    long sum_line = 0;
    int wait_time = 0;
    long line_wait = 0;
    for (int cycle = 0; cycle  < cyclelimit;cycle++)
    {
        if(newcustomer(min_per_cust))
        {
            if(line.isfull())
                turnaways++;
            else
            {
                customers++;
                temp.set(cycle);
                line.enqueue(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 acccepted: " << 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";
        cout << "Done!\n";
        return 0;

}
bool newcustomer(double x)
{
    return (std::rand() * x / RAND_MAX < 1);
}

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