标签：cin 循环 自动调用 因此 调用 add png 个数 析构
头文件stock00.h
1 //stock00.h 2 #ifndef STOCK00_H_ //如果没有定义STOCK00_H_ 3 #define STOCK00_H_ //那么就定义STOCK00_H_ 4 5 #include<string> 6 using namespace std; 7 8 class Stock //类声明 9 { 10 private: 11 string company; 12 long shares; 13 double share_val; 14 double total_val; 15 void set_tot(); 16 public: 17 void acquire(const string &co, long n, double pr); 18 void buy(long num, double price); 19 void sell(long num, double price); 20 void update(double price); 21 void show(); 22 }; 23 24 inline void Stock::set_tot() //内联函数 或者按书上那种写法，两种一样 25 { 26 total_val = shares*share_val; 27 } 28 29 #endif // !STOCK00_H_ 结束预定义
stock00.cpp
1 #include<iostream> 2 #include"stock00.h" 3 using namespace std; 4 5 void Stock::acquire(const string &co, long n, double pr) 6 { 7 company = co; 8 if (n < 0) 9 { 10 cout << "shares can‘t be negative." << company << " shares set to 0.\n"; 11 shares = 0; 12 } 13 else 14 shares = n; 15 share_val = pr; 16 set_tot(); 17 } 18 void Stock::buy(long num, double price) 19 { 20 if (num < 0) 21 cout << "shares purchased can‘t be negative.\n"; 22 else 23 { 24 shares += num; 25 share_val = price; 26 set_tot(); 27 } 28 } 29 void Stock::sell(long num, double price) 30 { 31 if (num < 0) 32 cout << "shares sold can‘t be negative.\n"; 33 else if (num > shares) 34 cout << "you can‘t sell more than you have.\n"; 35 else 36 { 37 shares -= num; 38 share_val = price; 39 set_tot(); 40 } 41 } 42 void Stock::update(double price) 43 { 44 share_val = price; 45 set_tot(); 46 } 47 void Stock::show() 48 { 49 cout << "Company: " << company 50 << " Shares: " << shares << "\n" 51 << " Share Price: $ " << share_val 52 << " Tptal Worth: & " << total_val << "\n"; 53 }
usestock0.cpp
1 #include<iostream> 2 #include"stock00.h" 3 using namespace std; 4 5 int main() 6 { 7 Stock cat; 8 cat.acquire("NanoSmart", 20, 12.50); 9 cat.show(); 10 cat.buy(15, 18.125); 11 cat.show(); 12 cat.sell(400, 20.0); 13 cat.show(); 14 cat.buy(300000, 40.125); 15 cat.show(); 16 cat.sell(300000, 0.125); 17 cat.show(); 18 19 system("pause"); 20 return 0; 21 }
修改stock.cpp文件中的show方法，使其数字格式统一
1 void Stock::show() 2 { 3 //将原始格式存入orig，设置cout对象的一个标记 4 //ios_base::fixed命令cout使用定点表示法，ios_base::floatfield设置输出时按浮点格式，小数点后有6位数 5 ios_base::fmtflags orig = cout.setf(ios_base::fixed, ios_base::floatfield); 6 //streamsize可以设置输入流的位数 7 //cout使用定点表示法时，显示三位小数 8 //保存当前流的位数到prec中 9 std::streamsize prec = cout.precision(3); 10 11 cout << "Company: " << company 12 << ", Shares:" << shares 13 << "\nShare Price: $" << share_val; 14 cout.precision(2); 15 cout << ", Total Worth: $" << total_val << ‘\n‘; 16 17 //返回调用show()之前的格式 18 cout.setf(orig, ios_base::floatfield); 19 cout.precision(prec); 20 }
头文件stock10.h
1 //stock10.h 2 #ifndef STOCK00_H_ //如果没有定义STOCK00_H_ 3 #define STOCK00_H_ //那么就定义STOCK00_H_ 4 5 #include<string> 6 using namespace std; 7 8 class Stock //类声明 9 { 10 private: 11 string company; 12 long shares; 13 double share_val; 14 double total_val; 15 void set_tot(); 16 public: 17 Stock(); //默认构造函数 18 Stock(const string &co, long n = 0, double pr = 0.0); //构造函数，和前面例子中的acquire()相同，区别在于，程序声明对象时，将自动调用构造函数 19 ~Stock(); //析构函数 20 void buy(long num, double price); 21 void sell(long num, double price); 22 void update(double price); 23 void show(); 24 }; 25 26 inline void Stock::set_tot() //内联函数 或者按书上那种写法，两种一样 27 { 28 total_val = shares*share_val; 29 } 30 31 #endif // !STOCK00_H_ 结束预定义
函数定义stock10.cpp
1 #include<iostream> 2 #include"stock10.h" 3 using namespace std; 4 5 //默认构造函数 6 Stock::Stock() 7 { 8 cout << "Default constructor called\n"; 9 company = "no name"; 10 shares = 0; 11 share_val = 0.0; 12 total_val = 0.0; 13 } 14 15 //构造函数 16 Stock::Stock(const string &co, long n, double pr) 17 { 18 cout << "Constructor using " << co << " called\n"; 19 company = co; 20 if (n < 0) 21 { 22 cout << "shares can‘t be negative." << company << " shares set to 0.\n"; 23 shares = 0; 24 } 25 else 26 shares = n; 27 share_val = pr; 28 set_tot(); 29 } 30 31 //析构函数 32 Stock::~Stock() 33 { 34 cout << "Bye, " << company << "!\n"; 35 } 36 37 //其他方法 38 void Stock::buy(long num, double price) 39 { 40 if (num < 0) 41 cout << "shares purchased can‘t be negative.\n"; 42 else 43 { 44 shares += num; 45 share_val = price; 46 set_tot(); 47 } 48 } 49 50 void Stock::sell(long num, double price) 51 { 52 if (num < 0) 53 cout << "shares sold can‘t be negative.\n"; 54 else if (num > shares) 55 cout << "you can‘t sell more than you have.\n"; 56 else 57 { 58 shares -= num; 59 share_val = price; 60 set_tot(); 61 } 62 } 63 void Stock::update(double price) 64 { 65 share_val = price; 66 set_tot(); 67 } 68 void Stock::show() 69 { 70 //将原始格式存入orig，设置cout对象的一个标记 71 //ios_base::fixed命令cout使用定点表示法，ios_base::floatfield设置输出时按浮点格式，小数点后有6位数 72 ios_base::fmtflags orig = cout.setf(ios_base::fixed, ios_base::floatfield); 73 //streamsize可以设置输入流的位数 74 //cout使用定点表示法时，显示三位小数 75 //保存当前流的位数到prec中 76 std::streamsize prec = cout.precision(3); 77 78 cout << "Company: " << company 79 << ", Shares:" << shares 80 << "\nShare Price: $" << share_val; 81 cout.precision(2); 82 cout << ", Total Worth: $" << total_val << ‘\n‘; 83 84 //返回调用show()之前的格式 85 cout.setf(orig, ios_base::floatfield); 86 cout.precision(prec); 87 }
主函数usestock1.cpp
1 #include<iostream> 2 #include"stock10.h" 3 using namespace std; 4 5 int main() 6 { 7 //大括号的作用：stock1和stock2等自动变量将在程序退出其定义所属代码块时消失 8 //如果没有大括号，代码块将为整个main()，因此main()执行完，到达返回语句之后，才会调用析构函数，会看不到最后两条消息。 9 { 10 cout << "Using constructors to create new objects\n"; 11 Stock stock1("NanoSmart", 12, 20.0); //隐式调用构造函数 12 stock1.show(); 13 Stock stock2 = Stock("Boffo Objects", 2, 2.0); //显式调用构造函数 14 stock2.show(); 15 16 cout << "Assigning stock1 to stock2!!!\n"; //将stock1分配给stock2!!！ 17 stock2 = stock1; 18 cout << "Listing stock1 and stock2:\n"; 19 stock1.show(); 20 stock2.show(); 21 22 cout << "Using a constructor to reset an object!!!\n"; //用构造函数重置对象 23 stock1 = Stock("Nifty Foods", 10, 50.0); 24 cout << "Revised stock1:\n"; //修订stock1 25 stock1.show(); 26 cout << "Done\n"; 27 } 28 system("pause"); 29 return 0; 30 }
红色标记为相较于上一个例子新增的东西
头文件stock20.h
1 //stock20.h 2 #ifndef STOCK00_H_ //如果没有定义STOCK00_H_ 3 #define STOCK00_H_ //那么就定义STOCK00_H_ 4 5 #include<string> 6 using namespace std; 7 8 class Stock //类声明 9 { 10 private: 11 string company; 12 long shares; 13 double share_val; 14 double total_val; 15 void set_tot(); 16 public: 17 Stock(); //默认构造函数 18 Stock(const string &co, long n = 0, double pr = 0.0); //构造函数，和前面例子中的acquire()相同，区别在于，程序声明对象时，将自动调用构造函数 19 ~Stock(); //析构函数 20 void buy(long num, double price); 21 void sell(long num, double price); 22 void update(double price); 23 //show()要加const，后面top要调用show(),是隐式访问的对象，所以类型要一致 24 void show()const; 25 //新增 26 const Stock & topval(const Stock & s)const; 27 }; 28 29 inline void Stock::set_tot() //内联函数 或者按书上那种写法，两种一样 30 { 31 total_val = shares*share_val; 32 } 33 34 #endif // !STOCK00_H_ 结束预定义
函数定义stock20.cpp
1 #include<iostream> 2 #include"stock20.h" 3 using namespace std; 4 5 //默认构造函数 6 Stock::Stock() 7 { 8 company = "no name"; 9 shares = 0; 10 share_val = 0.0; 11 total_val = 0.0; 12 } 13 14 //构造函数 15 Stock::Stock(const string &co, long n, double pr) 16 { 17 //cout << "Constructor using " << co << " called\n"; 18 company = co; 19 if (n < 0) 20 { 21 cout << "shares can‘t be negative." << company << " shares set to 0.\n"; 22 shares = 0; 23 } 24 else 25 shares = n; 26 share_val = pr; 27 set_tot(); 28 } 29 30 //析构函数 31 Stock::~Stock() 32 { 33 } 34 35 //其他方法 36 void Stock::buy(long num, double price) 37 { 38 if (num < 0) 39 cout << "shares purchased can‘t be negative.\n"; 40 else 41 { 42 shares += num; 43 share_val = price; 44 set_tot(); 45 } 46 } 47 48 void Stock::sell(long num, double price) 49 { 50 if (num < 0) 51 cout << "shares sold can‘t be negative.\n"; 52 else if (num > shares) 53 cout << "you can‘t sell more than you have.\n"; 54 else 55 { 56 shares -= num; 57 share_val = price; 58 set_tot(); 59 } 60 } 61 void Stock::update(double price) 62 { 63 share_val = price; 64 set_tot(); 65 } 66 void Stock::show()const 67 { 68 //将原始格式存入orig，设置cout对象的一个标记 69 //ios_base::fixed命令cout使用定点表示法，ios_base::floatfield设置输出时按浮点格式，小数点后有6位数 70 ios_base::fmtflags orig = cout.setf(ios_base::fixed, ios_base::floatfield); 71 //streamsize可以设置输入流的位数 72 //cout使用定点表示法时，显示三位小数 73 //保存当前流的位数到prec中 74 std::streamsize prec = cout.precision(3); 75 76 cout << "Company: " << company 77 << ", Shares:" << shares 78 << "\nShare Price: $" << share_val; 79 cout.precision(2); 80 cout << ", Total Worth: $" << total_val << ‘\n‘; 81 82 //返回调用show()之前的格式 83 cout.setf(orig, ios_base::floatfield); 84 cout.precision(prec); 85 } 86 87 //新增 88 const Stock & Stock::topval(const Stock & s)const 89 { 90 if (s.total_val > total_val) 91 return s; 92 else 93 return *this; 94 }
主函数usestock2.cpp （都改了，添加了对象数组）
1 #include<iostream> 2 #include"stock10.h" 3 using namespace std; 4 5 const int STKS = 4; 6 7 int main() 8 { 9 //创建一个初始化对象数组 10 Stock stocks[STKS] = 11 { 12 Stock("NS",12,20.0), 13 Stock("B O",200,2.0), 14 Stock("M O",130,3.25), 15 Stock("F E",60,6.5) 16 }; 17 cout << "Stock holding: " << endl; 18 int st; 19 for (st = 0; st < STKS; st++) 20 { 21 stocks[st].show(); 22 } 23 //让top指针指向第一个元素 24 const Stock *top = &stocks[0]; 25 //topval()每次只检查两个对象，所以程序使用for循环来检查整个数组 26 for (st = 1; st < STKS; st++) 27 { 28 top =&top -> topval(stocks[st]); //->的优先级高于&，所以可以看成top = & (top -> topval(stocks[st])); 29 //先用top调用topval(),将返回的对象的地址赋给top 30 } 31 cout << "\nmost valuable holding : \n"; 32 top->show(); 33 34 system("pause"); 35 return 0; 36 }
头文件stack.h
//stack.h #ifndef STACK_H_ //如果没有定义SSTACK_H_ #define STACK_H_ //那么就定义STACK_H_ typedef unsigned long Item; class Stack //类声明 { private: enum { MAX = 10 }; Item items[MAX]; int top; public: Stack(); //默认构造函数 bool isempty() const; bool isfull() const; bool push(const Item & item);//压栈 bool pop(Item & item);//出栈 }; #endif // !STOCK00_H_ 结束预定义
函数定义stack.cpp
1 #include "stack.h" 2 3 //构造函数 4 Stack::Stack() //创建一个空栈 5 { 6 top = 0; 7 } 8 9 bool Stack::isempty() const 10 { 11 return top == 0;//top为0返回true，反之为false 12 } 13 bool Stack::isfull() const 14 { 15 return top == MAX; 16 } 17 bool Stack::push(const Item &item) 18 { 19 if (top<MAX) 20 { 21 items[top++] = item; 22 return true; 23 } 24 else 25 return false; 26 } 27 bool Stack::pop(Item &item) 28 { 29 if (top>0) 30 { 31 item = items[--top]; 32 return true; 33 } 34 else 35 return false; 36 }
主函数stacker.cpp
1 #include<iostream> 2 #include<cctype> 3 #include "stack.h" 4 using namespace std; 5 6 void main() 7 { 8 Stack st; 9 char ch; 10 unsigned long po; 11 cout << "Enter A to add a purchase order, P to process a PO, Q to quit.\n"; 12 while (cin >> ch&&toupper(ch) != ‘Q‘) 13 { 14 while (cin.get() != ‘\n‘)//如果不是换行就继续 15 continue; 16 if (!isalpha(ch))//如果不是字母就继续 17 { 18 cout << ‘\a‘; 19 continue; 20 } 21 switch (ch) 22 { 23 case ‘A‘: 24 case ‘a‘: 25 cout << "Enter a PO number to add: "; 26 cin >> po; 27 if (st.isfull())//该方法判断：如果满了（top等于MAX）返回true，没满返回false 28 cout << "Stack already full\n"; 29 else 30 st.push(po); 31 break; 32 case ‘P‘: 33 case ‘p‘: 34 if (st.isempty()) 35 cout << "Stack already empty\n"; 36 else 37 { 38 st.pop(po); 39 cout << "PO #" << po << " popped\n"; 40 } 41 break; 42 } 43 cout << "Enter A to add a purchase order, P to process a PO, Q to quit.\n"; 44 } 45 system("pause"); 46 }
[C++ Primer Plus] 第10章、对象和类——（一）程序清单
标签：cin 循环 自动调用 因此 调用 add png 个数 析构
原文地址：https://www.cnblogs.com/Fionaaa/p/12705470.html
