extend

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1 (object oriented) Encapsulation Inheritance Polymorphism Dynamic Binding (base class) (derived class) 1

2 class Base { int I; void X(); void Y(); class Derived: public Base { private: int j; void z(); Derived j z() I X() Y() 2

3 class OLD { virtual void Action(); void OLD::Action(){ printf( This is an old class ); class New: public OLD { void Action(); void NEW::Action(){ printf( This is NEW class ); Action() New Action class Base{ virtual void Initialize(); void Base:: Initialize(){ /* class Derived: public Base{ void Initialize(); void Derived:: Initialize(){ Base::Initialize(); /* Base Initialize */ Derived Initialize */ 3

4 protected public, protected, private private protected public, protected, private public protected private 4

5 public class : public { /* */ public public protected public protected private class : private { /* */ private private public protected private private 5

6 public private public public private protected protected private private - class upcounter{ protected: int value; void set_val(int v) { value=v; void up() { value++; int get_val() { return value; 1 class counter: public upcounter{ void down() { value--; // upcounter a; counter b; a.set_val(5); b.set_val(8); for (int i=0;i<5;i++) { a.up(); b.up(); // for (i=0;i<10;i++) b.down(); cout << Value of counter a= << a.get_val() << \n ; // 10 cout << Value of counter b= ; // 3 6

7 - #include <math.h> class circle{ /* */ protected: double r; void set_radius(double a) { r=a; double area(){ return 4*atan(1)*r*r; class cylinder: public circle{ private: double h; void set_height(double a) { h=a; double area(){ double pi=4*atan(1); return pi*r*r*2+2*pi*r*h; circle c; cylinder b; c.set_radius(2); b.set_radius(2); b.set_height(2); cout << "Area of c ="<< c.area() <<"\n"; cout << "Surface of b="<< b.area() <<"\n"; Area of c= Surface of b= #include <stdlib.h> #include <conio.h> #include <time.h> - class Rockbox{ protected: int number; Rockbox(){ srand((unsigned)time(null)); number=1; void rock(){ number=rand()%9+1; int see(){ return number; class UnjustRock:public Rockbox{ void unjust(int); void UnjustRock::unjust(int no){ if ((no>=0)&&(no<=9)) number=n UnjustRock box1; cout << "; box1.rock(); cout<<box1.see()<<endl; cout<< "; box1.unjust(8); cout<<box1.see()<<endl; 7

8 #include <process.h> const int MAX=100; class Stack{ protected: int st[max]; int top; Stack(){ top=0; void push(int var){ st[++top]=var; int pop(){ return st[top--]; class Stack2:public Stack{ void push(int var); int pop(); - void Stack2::push( int var){ if (top<max) Stack::push(var); else { cout<<"\nerror:stack is full."; exit(1); int Stack2::pop(){ if (top>0) return Stack::pop(); else { cout<<"\n Error: Stack is empty."; exit(1); return -1; Stack2 s1; s1.push(110); s1.push(220); cout <<endl<<s1.pop(); // 220 cout <<endl<<s1.pop(); // 110 cout <<endl<<s1.pop(); ( ): ( ){ /* */ : Derived(int v): Base(v) 8

9 class Base{ Base(){ cout << In Base class\n ; class Derived: public Base{ Derived a; In Base class - #include <math.h> class vector2{ protected: double x,y; vector2(){x=0;y=0; vector2(double a, double b){ x=a; y=b; double len(){ return sqrt(x*x+y*y); class vector3: public vector2{ private: double z; vector3():vector2() {z=0; vector3(double a, double b, double c):vector2(a,b){ z=c; double len(){ return sqrt(x*x+y*y+z*z); vector2 p(3,-4); vector3 q(4,3,-5); cout << Length of point p= << p.len()<<endl; cout << Length of point q= << q.len()<<endl; 9

10 - class upcounter{ protected: int value; upcounter(){ value=0; upcounter(int v) { value=v; void up() { value++; int get_val() { return value; class counter: public upcounter{ counter():upcounter(){ counter(int v):upcounter(v) { void down() { value--; upcounter a(5); counter b(8); counter c; for (int i=0;i<5;i++) { a.up(); b.up(); for (i=0;i<10;i++) b.down(); cout << Value of counter a= <<a.get_val() << \n ; // 10 cout << Value of counter b= << b.get_val() << \n ; // 3 cout << "Value of counter c= " << c.get_val() <<"\n"; // 0 Step 1: Step 2: ( ): ( ){, ( ) 10

11 (1) class Base{ Base(){ cout << "Base class\n"; class Derived: public Base{ Derived():Base(){ Derived a; Base class Derived class // Derived(){ cout << "Derived class\n"; (2) class Base{ Base class Derived class 2 Base(){ cout << "Base class\n"; class Derived: public Base{ Derived(int j){ cout <<"Derived class " << j <<"\n"; Derived a(2); 11

12 (3) class Base{ Base(){ cout << "Base class\n"; Base(int j){ cout << "Base "<< j<<"\n"; class Derived: public Base{ Derived(int j):base (j){ cout <<"Derived class " << j <<"\n"; Derived a(2); Base 2 Derived class 2 (destructor) Step 1: Step 2: : class Base{ ~Base(){ cout<< In ~Base()\n ; class Derived: public Base{ ~Derived(){ cout<< In ~Derived()\n ; Derived p; In ~Derived() In ~Base() 12

13 (abstract class) (abstract class) ( ) (multiple inheritance) C++ (multiple inheritance) Derived Base1 Base2 Base 1 Base2 Base1 Base2 Derived 13

14 class : public 1, public 2 { private private : class Derived: public Base1, public Base2{ /* */ void set_grade(int n){ grade=n; #include <string.h> int get_grade(){ return grade; class man{ char name[20]; class student: public man, public cis{ int age; void disp(){ void set_name(char *p){ cout << Grade= <<grade<< \n ; strcpy(name,p); cout << Name= <<name<< \n ; char* get_name(){ return name; class cis{ // student john; protected: int grade; john.set_grade(1); john.set_name( John ); john.disp(); 14

15 - class A{ int x; void y(); class B{ int x; void y(); class C: public A, public B{ void set(); void C::set(){ x=0; // // y(); // :: :: : void C::set(){ A::x=0; B::y(); 15

16 class : public 1, public 2 : ( ): 1( ), 2( ) 1 2 class Base1{ Base1(){ cout<< Base 1\n ; class Base2{ Base2(){ cout<< Base 2\n ; class Derived: public Base1, public Base2{ Derived():Base1(),Base2(){ cout<< Derived class\n ; Derived a; Base 1 Base 2 Derived class 16

17 class : public 1, public 2 : ~ () 2 1 class Base1{ Base1(){ cout<<"in Base1\n"; ~Base1(){ cout<<"in ~Base1\n"; class Base2{ Base2(){ cout<<"in Base2\n"; ~Base2(){ cout<<"in ~Base2\n"; class Derived:public Base1, public Base2{ Derived():Base2(),Base1(){ cout << "In Derived\n"; ~Derived(){ cout << "In ~Derived\n"; Derived p; In Base1 In Base2 In Derived In ~Derived In ~Base2 In ~Base1 17

Strings

Strings Inheritance Cheng-Chin Chiang Relationships among Classes A 類別使用 B 類別學生使用手機傳遞訊息公司使用金庫儲存重要文件人類使用交通工具旅行 A 類別中有 B 類別汽車有輪子三角形有三個頂點電腦內有中央處理單元 A