Copyright © 2002 Pearson Education, Inc. Slide 1

Copyright © 2002 Pearson Education, Inc. Slide 2 Chapter 7 Created by Frederick H. Colclough, Colorado Technical University Constructors and Other Tools

Copyright © 2002 Pearson Education, Inc. Slide 3 Learning Objectives  Constructors  Definitions  Calling  More Tools  const parameter modifier  Inline functions  Static member data  Vectors  Introduction to vector class

Copyright © 2002 Pearson Education, Inc. Slide 4 物件函式 建立類別 建立物件 訊息 — 呼叫物件的成員函數

Copyright © 2002 Pearson Education, Inc. Slide 5 建立類別 定義類別 宣告資料成員 定義成員函數

Copyright © 2002 Pearson Education, Inc. Slide 6 定義類別 class 類別名稱 { 定義類別成員 }; 完成類別定義, 不要忘 了加上結尾符號 ;

Copyright © 2002 Pearson Education, Inc. Slide 7 class people { private: string name; public: void say_hello() }; 定義 people 類別 宣告 people 類別的 資料成員 完成類別定義, 不要忘 了加上結尾符號 ;

Copyright © 2002 Pearson Education, Inc. Slide 8 Constructor Definition Example  Class definition with constructor:  class DayOfYear { public: DayOfYear(int monthValue, int dayValue); //Constructor initializes month & day void input(); void output(); … private: int month; int day; }

Copyright © 2002 Pearson Education, Inc. Slide 9 將函數內容定義於類別內 class people { private: string name; public: void say_hello() { cout<<" Hello to You~."<<endl; } };

Copyright © 2002 Pearson Education, Inc. Slide 10 將函數內容定義於類別外 傳回型態 型態名稱 :: 成員函數名稱 ( 傳入參數 ) { 函數內容 …… }

Copyright © 2002 Pearson Education, Inc. Slide 11 將函數內容定義於類別外 class people { private: string name; public: void say_hello(); }; people :: say_hello() { cout<<" Hello to You~."<<endl; } 類別名稱 方法名稱 ( 函數名稱 )

Copyright © 2002 Pearson Education, Inc. Slide 12 建立物件 宣告方式 類別名稱 物件名稱 ; 例如： people John;

Copyright © 2002 Pearson Education, Inc. Slide 13 成員存取 物件名稱. 資料成員名稱 物件名稱. 成員函數名稱 ( 傳入變數 )

Copyright © 2002 Pearson Education, Inc. Slide 14 建立物件 int main() { people John; John.say_hello(); return 0; } 依據 people 類別 建立 John 物件 呼叫 John 物件的 成員函數

Copyright © 2002 Pearson Education, Inc. Slide 15 存取權限的控制 存取權限意義可存取的對象使用說明 public 公開級 程式內任何敘述均可 存取 以資訊隱藏的角度， 類別的資料成員應 該避免為 public private 私有級 1. 該類別的成員函數 2. 該類別的 friend 類別 或 friend 類別 以資訊隱藏的角度， 類別的資料應該盡 量定義為 private ，以 保護資料成員不被 任意存取 protected 保護級 1. 類別的成員函數 2. 繼承該類別之衍生 類別的成員函數 protected 等級介於 public 與 private 之間

Copyright © 2002 Pearson Education, Inc. Slide 16 存取權限 class 類別名稱 // 開始定義類別 { private: …… 宣告 private 等級成員的敘述 public: …… 宣告 public 等級成員的敘述 protected: …… 宣告 public 等級成員的敘述 }; // 類別定義結束

Copyright © 2002 Pearson Education, Inc. Slide 17 class people { public: string name; void say-hello() { cout<<" Hello to You~."<<endl; } people(string text); }; people::people(string text) { name=text; } int main() { people Student("John"); cout<<Student.name<<" : "; Student.say-hello(); return 0; } people 的建構子 呼叫 Student 的名字 呼叫 say-hello 的方法

Copyright © 2002 Pearson Education, Inc. Slide 18 class people { private: string name; public: void say_hello() { cout<<" Hello to You~."<<endl; } people(string text); }; people::people(string text) { name=text; } int main() { people Student("John"); cout<<Student.name<<" : "; Student.say_hello(); return 0; } name 是 private 類別 因為 name 是 private 等級, 所以不能直接 呼叫

Copyright © 2002 Pearson Education, Inc. Slide 19 class people { private: string name; public: void say_hello() { cout<<" Hello to You~."<<endl; } people(string text); string getName(); }; people::people(string text) { name=text; } string people::getName() { return name; } int main() { people Student("John"); cout<<Student.getName()<<" : "; Student.say_hello(); return 0; } 呼叫 people 的 getName() 方法 ( 函數 ) 利用 people 類別的 getName() 方法 ( 函數 ) 回傳 name

Copyright © 2002 Pearson Education, Inc. Slide 20 定義類別時的不能初始化資料 class people { private: string name; int age=1; double hight,weight; public: void say_hello() void show_information(); string getName(); }; 定義類別時的不 能初始化資料 利用建構子初始化 物件的初值

Copyright © 2002 Pearson Education, Inc. Slide 21 Constructors  Initialization of objects  Initialize some or all member variables  Other actions possible as well  A special kind of member function  Automatically called when object declared  Very useful tool  Key principle of OOP

Copyright © 2002 Pearson Education, Inc. Slide 22 Constructor Definitions  Constructors defined like any member function  Except: 1. Must have same name as class 2. Cannot return a value; not even void!

Copyright © 2002 Pearson Education, Inc. Slide 23 Constructor Code  Constructor definition is like all other member functions: DayOfYear::DayOfYear(int monthValue, int dayValue) { month = monthValue; day = dayValue; }  Note same name around ::  Clearly identifies a constructor  Note no return type  Just as in class definition

Copyright © 2002 Pearson Education, Inc. Slide 24 建構子定義於類別內 class people { private: string name; int age; double hight,weight; public: people(string p_name,int p_age,double p_hight, double p_weight); // 建立建構子，傳入四個資料參數 };

Copyright © 2002 Pearson Education, Inc. Slide 25 Alternative Definition  Previous definition equivalent to: DayOfYear::DayOfYear(int monthValue, int dayValue) : month(monthValue), day(dayValue)  {…}  Third line called ‘Initialization Section’  Body left empty  Preferable definition version

Copyright © 2002 Pearson Education, Inc. Slide 26 建構子定義於類別內 class people{ private: string name; int age; double hight,weight; public: people(string p_name,int p_age,double p_hight,double p_weight) { name=p_name; age=p_age; hight=p_hight; weight=p_weight; };

Copyright © 2002 Pearson Education, Inc. Slide 27 建構子定義於類別外 class people { private: string name; int age; double hight,weight; public: people(string p_name,int p_age,double p_hight, double p_weight); // 建立建構子，傳入四個資料參數 };

Copyright © 2002 Pearson Education, Inc. Slide 28 建構子定義於類別外 people::people(string p_name,int p_age,double p_hight,double p_weight) { name=p_name; age=p_age; hight=p_hight; weight=p_weight; } 類別名稱 :: 類別名稱

Copyright © 2002 Pearson Education, Inc. Slide 29 Constructor Additional Purpose  Not just initialize data  Body doesn’t have to be empty  In initializer version  Validate the data!  Ensure only appropriate data is assigned to class private member variables  Powerful OOP principle

Copyright © 2002 Pearson Education, Inc. Slide 30 成員起始序 (Memeber initialization list) 類別名稱 ( 參數列 ) : 資料成員 ( 初值 ) ，資料成員 ( 初值 )….. { ……} people::people(string p_name,int p_age,double p_hight,double p_weight) :name(p_name),age(p_age),hight(p_hight),weight(p_weight){ } 宣告建構子的同時，以 : 開始， 宣告每個資料成員的初值 編輯其他初使值，若 不需要時就空著

Copyright © 2002 Pearson Education, Inc. Slide 31 成員起始序 (Memeber initialization list) 類別名稱 ( 參數列 ) : 資料成員 ( 初值 ) ，資料成員 ( 初值 )….. { ……} people::people(string p_name,int p_age,double p_hight,double p_weight) :name(p_name),age(p_age) { hight = p_hight * 0.9; weight = p_hight * 1.2; } 宣告建構子的同時，以 : 開始， 宣告每個資料成員的初值 另外編輯其他初使值

Copyright © 2002 Pearson Education, Inc. Slide 32 物件的產生 _ 建構子 利用類別的成員函數，執行資料的初值設定。 建構子的存取權限等級不會被宣告為 private ， 否則宣告物件時，建構子將無法被呼叫。 建構子大部分被定義為 public ，某些情形是 定義為 protected 。 建構子沒有回傳值。

Copyright © 2002 Pearson Education, Inc. Slide 33 Constructor Notes  Notice name of constructor: DayOfYear  Same name as class itself!  Constructor declaration has no return-type  Not even void!  Constructor in public section  It’s called when objects are declared  If private, could never declare objects!

Copyright © 2002 Pearson Education, Inc. Slide 34 Calling Constructors  Declare objects: DayOfYear date1(7, 4), date2(5, 5);  Objects are created here  Constructor is called  Values in parens passed as arguments to constructor  Member variables month, day initialized: date1.month  7date2.month  5 date1.dat  4date2.day  5

Copyright © 2002 Pearson Education, Inc. Slide 35 Constructor Equivalency  Consider:  DayOfYear date1, date2 date1.DayOfYear(7, 4);// ILLEGAL! date2.DayOfYear(5, 5);// ILLEGAL!  Seemingly OK…  CANNOT call constructors like other member functions!

Copyright © 2002 Pearson Education, Inc. Slide 36 作業 _4_ 建立物件 物件：學生名單 class NameList{ private: string _list[10][2]; public: string get_Name(string num); string get_Num(string name); void set_Name(string num,string name); void Display(); NameList(string List[10][2]); };

Copyright © 2002 Pearson Education, Inc. Slide 37 string _list[10][2]; 功能：學生名單存取學生學號和學生姓名 可以存 10 位學生的學號和姓名 _list[i][0]: 第 i 位學生的學號 _list[i][1]: 第 i 位學生的姓名

Copyright © 2002 Pearson Education, Inc. Slide 38 NameList 的功能 string get_Name(string num): 輸入學號 num ，查詢學生姓名 string get_Num(string name) : 輸入學生姓名 name ，查詢學生學號 void set_Name(string num,string name): 更改學號為 num 的學生姓名，更改為 name 如 :namelist.set_Name(“ ”,” 劉家佑 ”) 將學號為 ” ” 的學生姓名改為叫 ” 劉家佑 ” void Display(): 列印出學生名單

Copyright © 2002 Pearson Education, Inc. Slide 39 建構子 NameList(string List[10][2]); 輸入一個 List[10][2] 的陣列， 將資料存到 _list[10][2] 陣列中

Copyright © 2002 Pearson Education, Inc. Slide 40 主程式 學生名單功能界面請參考網路上的主程式內容， 請不要修改主程式的內容， 只需要將 NameList 物件的程式捕齊

Copyright © 2002 Pearson Education, Inc. Slide 41 String C++ 所提供的字串類別 使用 string 類別時，必須載入 string 標頭檔 #include

Copyright © 2002 Pearson Education, Inc. Slide 42 String 的六種建構子 string() string(const charT* s); string(const charT* s, size_type n); string(size_type n, charT c); string(const basic_string& str, size_type pos=0, size_type n=npos); string(InputIterators begin, InputIterators end);

Copyright © 2002 Pearson Education, Inc. Slide 43 String 的建構方式 string s0 ; -- 宣告一個沒有資料的字串 string s1(“HI~Everybody”); -- 利用字串建立物件 string s2(s1); -- 利用 s1 字串類別建立 s2 字串 string s3(s1,3,9);-- 利用 s1 字串物件第 3 個字之後 9 個字元建立 s3 字串物件 string s4(5,’!’); -- 建立五個 ! 的字串 string s6=s1; -- 複製 s1 字串物件給 s6

Copyright © 2002 Pearson Education, Inc. Slide 44 string(InputIterators begin, InputIterators end) char p1[12]=“HI~Everybody”; string s5(p1+3,p1+12); //s5 字串由 p1 陣列中第 3 個字串到第 12 個字串組成  s5=“Everybody”;

Copyright © 2002 Pearson Education, Inc. Slide 45 字串的指派、互換、移除 、 插入與截取 函數用途使用範例說明 assign 將字串指派給 另外一個字串 s2.assign(s1) 將 s1 指派給 s2 swap 互換 s1 和 s2 s2.swap(s1) 將 s1 和 s2 字串 互換 erase 將字串中一些 字元移除 s1.erase(3,5) 將字串中第 3 個 字元之後的 5 個 字元都移除 insert 將字串插入 s1.insert(2,”HI”) 將 ”HI” 字串插 入 s1 的第 2 個字 元後

Copyright © 2002 Pearson Education, Inc. Slide 46 字串的指派、互換、移除 、 插入與截 取 函數用途使用範例說明 substr 截取字串中的 字元 s1.substr(3,5) 截取 s1 第 3 個字 元後 5 個字元

Copyright © 2002 Pearson Education, Inc. Slide 47 string s0; string s1(“HI~Everybody”); string s2(s1,3,9); s0.assign(s1); cout<<"s0="<<s0<<endl; cout<<"s2="<<s2<<endl; s0.swap(s2); cout<<"s0="<<s0<<endl; cout<<"s2="<<s2<<endl; s0=“HI~Everybody” s0=“” s2=“Everybody” s0=“Everybody” S2=“HI~Everybody”

Copyright © 2002 Pearson Education, Inc. Slide 48 s2.erase(3,5); cout<<"s2="<<s2<<endl; s2.insert(3,"No"); cout<<"s2="<<s2<<endl; s2=s0.substr(5,4); cout<<"s2="<<s2<<endl; s0=“Everybody” s2=“HI~Everybody” s2=“HI~body” s2=“HI~Nobody” s2=“body”

Copyright © 2002 Pearson Education, Inc. Slide 49 比較字串中的字元 -compare compare— 比較兩字串的順序大小，且是根據 英文字母排列的順序比較 且是大寫字母大於小寫字母  s1.compaer(s2) 若 s1 排列順序在 s2 前面，則回傳值將小於 0 若 s1 排列順序和 s2 相同，則回傳值將等於 0 若 s1 排列順序在 s2 之後，則回傳值將大於 0

Copyright © 2002 Pearson Education, Inc. Slide 50 比較字串中的字元 -compare string s0("Everybody"); string s1("HI~Everybody"); string s2("EverybodY"); string s3(s0); cout<<s0.compare(s1)<<endl; cout<<s0.compare(s2)<<endl; cout<<s0.compare(s3); Everybody HI~Everybody Everybody EverybodY Everybody

Copyright © 2002 Pearson Education, Inc. Slide 51 比較字串中的字元 -compare 比較 s1,s2 兩個字串是否相等 s1.compare(s2)  看這值是否為 0 if(s1.compare(s2)==0)  代表 s1 和 s2 的字串相等

Copyright © 2002 Pearson Education, Inc. Slide 52 尋找與置換字串中的字元 函數用途使用範例說明 find 尋找字串中 的字元 s1.find(“ing”) 尋找 s1 中是 否存在 ing 字 串, 並傳回起 始字元的索 引值 repla ce 置換字串 s1.replace(3,2,”ed”) 將 s1 字串中 第 4 個後 2 個 字元換成 ed

Copyright © 2002 Pearson Education, Inc. Slide 53 replace 和 find 並用，直接找尋置換的字串 s1.replace(s1.find( 想要換掉的字串 ), 置換字串長度, 置換字串 ) s1.replace(s1.find(“ing”),2,”ed”); 例子 2: string s1(“HI~Everybody”); s1.replace(s1.find(“Every”),3,”Any”);  s1 變為 “Hi~Anybody”

Copyright © 2002 Pearson Education, Inc. Slide 54 取得字串資訊 函數用途使用範例說明 size() 傳回字串的長 度 ( 字元個數 ) s1.size() 傳回 s1 的 字串長度 max_size() 傳回可宣告最 大字串的長度 s1.max_size() 傳回 s1 可 能容納的 最大字元 數 empty() 若為空字串， 則傳回真 s1.empty() s1 是否為 空字串

Copyright © 2002 Pearson Education, Inc. Slide 55 Vectors  Vector Introduction  Recall: arrays are fixed size  Vectors: ‘arrays that grow and shrink’  During program execution  Formed from Standard Template Library (STL)  Using template class

Copyright © 2002 Pearson Education, Inc. Slide 56 STL (Standard Template Library) 標準樣版程式庫 : 將設計程式裡經常用到的基本資料結構與演算 法，建立為可供程式設計師套用的程式庫 STL 裡提供許多容器，每一種容器就是一種儲 存資料的方法，可以在這容器中放入任何型別 的資料，或是自行定義的類別。

Copyright © 2002 Pearson Education, Inc. Slide 57 vector 可以當做智慧型的陣列，在記憶體中佔有一塊 連續的空間。 和陣列的相異處： (1) vector 是動態處理記憶體大小，宣告時不會 被要求宣告固定的儲存空間。 (2) 可以存取個種類型資料，包括自行定義的類 別。

Copyright © 2002 Pearson Education, Inc. Slide 58 vector 的使用 必須載入 vector 標頭檔 -- #include 宣告 vector -- vector 變數名稱 資料型態 --vector 容器內欲儲存的資料型態 變數名稱 -- 運用 vector 容器宣告之物件名稱

Copyright © 2002 Pearson Education, Inc. Slide 59 vector 容器在記憶體中儲存方法 前端 末端

Copyright © 2002 Pearson Education, Inc. Slide 60 vector 的成員函數 名稱用途 插入與刪除 push_back 在容器末端增加元素 pop_back 在容器末端刪除元素 insert 在容器中間插入元素 erase 刪除容器中間的元素 clear 清除容器內的元素 其他重要的函式 size 傳回目前容器中的元素個數 empty 若容器內無元素傳回 true, 反之傳回 false

Copyright © 2002 Pearson Education, Inc. Slide 61 vector 的成員函數 名稱用途 其他重要的函式 size 傳回目前容器中的元素個數 empty 若容器內無元素傳回 true, 反之傳回 false begin 傳入容器前端的位置 end 傳入容器後端的位置

Copyright © 2002 Pearson Education, Inc. Slide 62 宣告儲存 int 型態的 vector vector v1; v.push_back(1);  存入 1 到 vector[0] 裡 v.push_back(2);  存入 2 到 vector[1] 裡 v.push_back(3);  存入 3 到 vector[2] 裡 v.insert(v.begin()+1,4);  將 4 插入 1 的位置 前端 末端 1234

Copyright © 2002 Pearson Education, Inc. Slide 63 新增 vector 內儲存的資料 新增 vector 內第 i 個位置的資料 v.insert(v.begin()+i, 新增的資料 ) 新增 vector 末端的資料 v.push_back( 新增的資料 )

Copyright © 2002 Pearson Education, Inc. Slide 64 刪除 vector 內儲存的資料 刪除 vector 內第 i 個位置的資料 v.erase(v.begin()+i) 刪除 vector 末端的資料 v.pop_back() 清除容器內所有資料 v.clear()

Copyright © 2002 Pearson Education, Inc. Slide 65 修改 vector 內儲存的資料 修改 vector 內第 i 個位置的資料 v[i]= 修改的資料

Copyright © 2002 Pearson Education, Inc. Slide 66 列印 vector 內的所有資料 for(int i=0;i<v.size();i++)  i 小於 v 的容量大小 cout<<v[i]<<endl;  直接列印 v[i] 的值

Copyright © 2002 Pearson Education, Inc. Slide 67 vector 儲存自行定義的類別 class people{ }; 若自行定義了 people 類別 int main() { vector namelist;  可以存取 people 物件 }

Copyright © 2002 Pearson Education, Inc. Slide 68 vector 儲存自行定義的類別 vector NameList; people John(“John”,22,175.5,64.5);  建立 John 物件 people Mary("Mary",23,165.5,48.5);  建立 Mary 物件 NameList.push_back(John);  存入 John NameList.push_back(Mary);  存入 Mary

Copyright © 2002 Pearson Education, Inc. Slide 69 Vector Basics  Similar to array:  Has base type  Stores collection of base type values  Declared differently:  Syntax: vector  Indicates template class  Any type can be ‘plugged in’ to Base_Type  Produces ‘new’ class for vectors with that type  Example declaration: vector v;

Copyright © 2002 Pearson Education, Inc. Slide 70 Vector Use  vector v;  ’v is vector of type int’  Calls class default constructor  Empty vector object created  Indexed like arrays for access  But to add elements:  Must call member function push_back  Member function size()  Returns current number of elements

Copyright © 2002 Pearson Education, Inc. Slide 71 Vector Efficiency  Member function capacity()  Returns memory currently allocated  Not same as size()  Capacity typically > size  Automatically increased as needed  If efficiency critical:  Can set behaviors manually  v.reserve(32); //sets capacity to 32  v.reserve(v.size()+10); //sets capacity to 10 more than size

Copyright © 2002 Pearson Education, Inc. Slide 72 Overloaded Constructors  Can overload constructors just like other functions  Recall: a signature consists of:  Name of function  Parameter list  Provide constructors for all possible argument-lists  Particularly ‘how many’

Copyright © 2002 Pearson Education, Inc. Slide 73 Constructor with No Arguments  Can be confusing  Standard functions with no arguments:  Called with syntax: callMyFunction();  Including empty parentheses  Object declarations with no ‘initializers’:  DayOfYear date1;// This way!  DayOfYear date(); // NO!  What is this really?  Compiler sees a function declaration/prototype!  Yes! Look closely!

Copyright © 2002 Pearson Education, Inc. Slide 74 Explicit Constructor Calls  Can also call constructor AGAIN  After object declared  Recall: constructor was automatically called then  Can call via object’s name; standard member function call  Convenient method of setting member variables  Method quite different from standard member function call

Copyright © 2002 Pearson Education, Inc. Slide 75 Explicit Constructor Call Example  Such a call returns ‘anonymous object’  Which can then be assigned  In Action: DayOfYear holiday(7, 4);  Constructor called at object’s declaration  Now to ‘re-initialize’: holiday = DayOfYear(5, 5);  Explicit constructor call  Returns new ‘anonymous object’  Assigned back to current object

Copyright © 2002 Pearson Education, Inc. Slide 76 Default Constructor  Defined as: constructor w/ no arguments  One should always be defined  Auto-Generated?  Yes & No  If no constructors AT ALL are defined  Yes  If any constructors are defined  No  If no default constructor:  Cannot declare: MyClass myObject;  With no initializers

Copyright © 2002 Pearson Education, Inc. Slide 77 Class Type Member Variables  Class member variables can be any type  Including objects of other classes!  Type of class relationship  Powerful OOP principle  Need special notation for constructors  So they can call ‘back’ to member object’s constructor

Copyright © 2002 Pearson Education, Inc. Slide 78 Parameter Passing Methods  Efficiency of parameter passing  Call-by-value  Requires copy be made  Overhead  Call-by-reference  Placeholder for actual argument  Most efficient method  Negligible difference for simple types  For class types  clear advantage  Call-by-reference desirable  Especially for ‘large’ data, like class types

Copyright © 2002 Pearson Education, Inc. Slide 79 The const Parameter Modifier  Large data types (typically classes)  Desirable to use pass-by-reference  Even if function will not make modifications  Protect argument  Use constant parameter  Also called constant call-by-reference parameter  Place keyword const before type  Makes parameter ‘read-only’  Attempts to modify result in compiler error

Copyright © 2002 Pearson Education, Inc. Slide 80 Use of const  All-or-nothing  If no need for function modifications  Protect parameter with const  Protect ALL such parameters  This includes class member function parameters

Copyright © 2002 Pearson Education, Inc. Slide 81 Inline Functions  For non-member functions:  Use keyword inline in function declaration and function heading  For class member functions:  Place implementation (code) for function IN class definition  automatically inline  Use for very short functions only  Code actually inserted in place of call  Eliminates overhead  More efficient, but only when short!

Copyright © 2002 Pearson Education, Inc. Slide 82 Inline Member Functions  Member function definitions  Typically defined separately, in different file  Can be defined IN class definition  Makes function ‘in-line’  Again: use for very short functions only  More efficient  If too long  actually less efficient!

Copyright © 2002 Pearson Education, Inc. Slide 83 Static Members  Static member variables  All objects of class ‘share’ one copy  One object changes it  all see change  Useful for ‘tracking’  How often a member function is called  How many objects exist at given time  Place keyword static before type

Copyright © 2002 Pearson Education, Inc. Slide 84 Static Functions  Member functions can be static  If no access to object data needed  And still ‘must’ be member of the class  Make it a static function  Can then be called outside class  From non-class objects:  E.g.: Server::getTurn();  As well as via class objects  Standard method: myObject.getTurn();  Can only use static data, functions!

Copyright © 2002 Pearson Education, Inc. Slide 85 Summary 1  Constructors: automatic initialization of class data  Called when objects are declared  Constructor has same name as class  Default constructor has no parameters  Should always be defined  Class member variables  Can be objects of other classes  Require initialization-section

Copyright © 2002 Pearson Education, Inc. Slide 86 Summary 2  Constant call-by-reference parameters  More efficient than call-by-value  Can inline very short function definitions  Can improve efficiency  Static member variables  Shared by all objects of a class  Vector classes  Like: ‘arrays that grow and shrink’