第十章

README.md

@@ -35,8 +35,8 @@
 
 **第 II 部分 : 类设计者的工具**
 
-- [第 10 章 : 对象和类](practice/chapter10/README.md)
-- [第 11 章 : 实用类](practice/chapter11/README.md)
+- [第 10 章 : 对象和类](practice/chapter10/README.md) | ([笔记](practice/booknotes.md#第十章-对象和类))
+- [第 11 章 : 使用类](practice/chapter11/README.md)
 - [第 12 章 : 类和动态内存分配](practice/chapter12/README.md)
 - [第 13 章 : 类继承](practice/chapter13/README.md)
 

source/chapter10/stack.cpp

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+// stack.cpp -- Stack member functions
+#include "stack.h"
+Stack::Stack()    // create an empty stack
+{
+    top = 0;
+}
+
+bool Stack::isempty() const
+{
+    return top == 0;
+}
+
+bool Stack::isfull() const
+{
+    return top == MAX;
+}
+
+bool Stack::push(const Item & item) 
+{
+    if (top < MAX)
+    {
+        items[top++] = item;
+        return true;
+    }
+    else
+        return false;
+}
+
+bool Stack::pop(Item & item)
+{
+    if (top > 0)
+    {
+        item = items[--top];
+        return true;
+    }
+    else
+        return false; 
+}

source/chapter10/stack.h

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+// stack.h -- class definition for the stack ADT
+#ifndef STACK_H_
+#define STACK_H_
+
+typedef unsigned long Item;
+
+class Stack
+{
+private:
+    enum {MAX = 10};    // constant specific to class
+    Item items[MAX];    // holds stack items
+    int top;            // index for top stack item
+public:
+    Stack();
+    bool isempty() const;
+    bool isfull() const;
+    // push() returns false if stack already is full, true otherwise
+    bool push(const Item & item);   // add item to stack
+    // pop() returns false if stack already is empty, true otherwise
+    bool pop(Item & item);          // pop top into item
+};
+#endif

source/chapter10/stacker.cpp

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+// stacker.cpp -- testing the Stack class
+#include <iostream>
+#include <cctype>  // or ctype.h
+#include "stack.h"
+int main()
+{
+    using namespace std;
+    Stack st; // create an empty stack
+    char ch;
+    unsigned long po;
+    cout << "Please enter A to add a purchase order,\n"
+        << "P to process a PO, or Q to quit.\n";
+    while (cin >> ch && toupper(ch) != 'Q')
+    {
+        while (cin.get() != '\n')   
+            continue;
+        if (!isalpha(ch))
+        {
+            cout << '\a';
+            continue;
+        }
+        switch(ch)
+        {
+             case 'A':
+             case 'a': cout << "Enter a PO number to add: ";
+                       cin >> po;
+                       if (st.isfull())
+                           cout << "stack already full\n";
+                       else
+                           st.push(po);
+                       break;
+             case 'P':
+             case 'p': if (st.isempty())
+                           cout << "stack already empty\n";
+                       else {
+                           st.pop(po);
+                           cout << "PO #" << po << " popped\n";
+                       }
+                       break;
+        }
+        cout << "Please enter A to add a purchase order,\n"
+             << "P to process a PO, or Q to quit.\n";
+    }
+    cout << "Bye\n";
+    return 0; 
+}

source/chapter10/stock00.cpp

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+// stock00.cpp -- implementing the Stock class
+// version 00
+#include <iostream>
+#include "stock00.h"
+
+void Stock::acquire(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();
+}
+
+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()
+{
+    std::cout << "Company: " << company
+              << "  Shares: " << shares << '\n'
+              << "  Share Price: $" << share_val
+              << "  Total Worth: $" << total_val << '\n';
+}

source/chapter10/stock00.h

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+// stock00.h -- Stock class interface
+// version 00
+#ifndef STOCK00_H_
+#define STOCK00_H_
+
+#include <string>  
+
+class Stock  // class declaration
+{
+private: 
+    std::string company;
+    long shares;
+    double share_val;
+    double total_val;
+    void set_tot() { total_val = shares * share_val; }
+public:
+    void acquire(const std::string & co, long n, double pr);
+    void buy(long num, double price);
+    void sell(long num, double price);
+    void update(double price);
+    void show();
+};    // note semicolon at the end
+
+#endif

source/chapter10/stock01.cpp

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+// stock01.cpp -- revised show() method
+#include <iostream>
+#include "stock00.h"
+
+void Stock::acquire(const std::string & co, long n, double pr)
+{
+    company = co;
+    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();
+}
+
+void Stock::buy(long 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(long 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::ios_base;
+    // set format to #.###
+    ios_base::fmtflags orig = cout.setf(ios_base::fixed); 
+    int prec = cout.precision(3);
+
+    cout << "Company: " << company
+        << "  Shares: " << shares << '\n';
+    cout << "  Share Price: $" << share_val;
+    // set format to *.**
+    cout.precision(2);
+    cout << "  Total Worth: $" << total_val << '\n';
+
+    // restore original format
+    cout.setf(orig, ios_base::floatfield);
+    cout.precision(prec);
+}

source/chapter10/stock10.cpp

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+// stock1.cpp – Stock class implementation with constructors, destructor added
+#include <iostream>
+#include "stock10.h"
+
+// constructors (verbose versions)
+Stock::Stock()        // default constructor
+{
+    std::cout << "Default constructor called\n";
+    company = "no name";
+    shares = 0;
+    share_val = 0.0;
+    total_val = 0.0;
+}
+
+Stock::Stock(const std::string & co, long n, double pr)
+{
+    std::cout << "Constructor using " << co << " called\n";
+    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();
+}
+// class destructor
+Stock::~Stock()        // verbose class destructor
+{
+    std::cout << "Bye, " << company << "!\n";
+}
+
+// other methods
+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()
+{
+    using std::cout;
+    using std::ios_base;
+    // set format to #.###
+    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 << "  Share Price: $" << share_val;
+    // set format to #.##
+    cout.precision(2);
+    cout << "  Total Worth: $" << total_val << '\n';
+
+    // restore original format
+    cout.setf(orig, ios_base::floatfield);
+    cout.precision(prec);
+}