1 / 14

Chapter 6: Classes and Data Abstraction

Chapter 6: Classes and Data Abstraction. Outline 6.1 Introduction 6.2 Structure Definitions 6.3 Accessing Members of Structures 6.4 Implementing a User-Defined Type Time with a Struct 6.5 Implementing a Time Abstract Data Type with a Class 6.6 Class Scope and Accessing Class Members

obert
Download Presentation

Chapter 6: Classes and Data Abstraction

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chapter 6: Classes andData Abstraction Outline 6.1 Introduction 6.2 Structure Definitions 6.3 Accessing Members of Structures 6.4 Implementing a User-Defined Type Time with a Struct 6.5 Implementing a Time Abstract Data Type with a Class 6.6Class Scope and Accessing Class Members 6.7 Separating Interface from Implementation 6.8 Controlling Access to Members 6.9 Access Functions and Utility Functions 6.10 Initializing Class Objects: Constructors 6.11 Using Default Arguments with Constructors 6.12 Using Destructors 6.13 When Constructors and Destructors Are Called 6.14 Using Data Members and Member Functions 6.15 A Subtle Trap: Returning a Reference to a Private Data Member 6.16 Assignment by Default Memberwise Copy 6.17 Software Reusability

  2. 6.6 Class Scope and Accessing Class Members • 클래스 범위(Class scope) • 데이터멤버, 멤버함수를 직접 이름으로 접근 • 클래스 외부 범위 • 데이터와 멤버함수는 클래스 핸들을 통해 접근 • 예: t.printStadard(), t->printStandard • 함수범위(Function scope) • 변수는 정의된 함수 내에서만 알려짐 • 함수 수행이 종료되면 변수도 소멸됨

  3. 6.6 Class Scope and Accessing Class Members • 클래스 멤버의 접근 • Structs와 동일함 • 객체의 경우 도트(.), 포인터의 경우 화살표(->)를 사용함 • 예: • t.hour는 t의 hour요소임 • TimePtr->hour역시 hour요소임

  4. 1. Class definition2. Create an object of the class2.1 Assign a value to the object. Print the value using the dot operator2.2 Set a new value and print it using a reference 1 // Fig. 6.4: fig06_04.cpp 2 // Demonstrating the class member access operators . and -> It is rare to have public member variables. Usually only member functions are public; this keeps as much information hidden as possible. 3 // 4 // CAUTION: IN FUTURE EXAMPLES WE AVOID PUBLIC DATA! 5 #include <iostream> 6 7 using std::cout; 8 using std::endl; 9 10 // Simple class Count 11 class Count { 12 public: 13 int x; 14 void print() { cout << x << endl; } 15 }; 16 17 int main() 18 { 19 Count counter, // create counter object 20 *counterPtr = &counter, // pointer to counter 21 &counterRef = counter; // reference to counter 22 23 cout << "Assign 7 to x and print using the object's name: "; 24 counter.x = 7; // assign 7 to data member x 25 counter.print(); // call member function print 26 27 cout << "Assign 8 to x and print using a reference: "; 28 counterRef.x = 8; // assign 8 to data member x 29 counterRef.print(); // call member function print 30 1. Class definition2. Create an object of the class2.1 Assign a value to the object. Print the value using the dot operator2.2 Set a new value and print it using a reference

  5. 31 cout << "Assign 10 to x and print using a pointer: "; 32 counterPtr->x = 10; // assign 10 to data member x 33 counterPtr->print(); // call member function print 34 return 0; 35 } 2.3 Set a new value and print it using a pointerProgram Output Assign 7 to x and print using the object's name: 7 Assign 8 to x and print using a reference: 8 Assign 10 to x and print using a pointer: 10

  6. 6.7 Separating Interface from Implementation • 인터페이스를 구현으로부터 분리 • 프로그램 수정을 용이하도록 함 • 해더파일(Header files) • 클래스 정의와 함수 원형을 저장 • 소스코드 파일 (Source-code files) • 멤버 함수의 정의를 포함

  7. File  New Project

  8. Project  Add to Project

  9. Execute  Rebuild All Execute  Compile and Run

  10. # Compiler CC=g++ # Parameters given to the compiler CFLAGS=-s -IC:\DEV-C_~1\Include\ -IC:\DEV-C_~1\Include\G__~1 -IC:\DEV-C_~1\Include\ -LC:\DEV-C_~1\Lib\ -BC:\DEV-C_~1\Bin\ # Output filename (*.exe) OUTPUT="week2-HGD.exe" # Source files SRCS="C:\Fig6_05\WorkTime.cpp" "C:\\Fig6_05\test.cpp" # Output object files (*.o) OBJS="C:\Fig6_05\WorkTime.o" "C:\Fig6_05\test.o" "C:\Fig6_05\rsrc.o" # Standard targets all: compile_res $(CC) -c $(SRCS) $(CFLAGS) $(CC) -o $(OUTPUT) $(OBJS) $(CFLAGS) compile_res: windres --include-dir C:\DEV-C_~1\Include\ --include-dir C:\DEV-C_~1\Include\G__~1 --include-dir C:\DEV-C_~1\Include\ --use-temp-file -I rc -O coff -i "C:\강의\2003-2\프로그~1\ch06\Fig6_05\rsrc.rc" -o "C:\강의\2003-2\프로그~1\ch06\Fig6_05\rsrc.o" Makefile의 내용

  11. 1 //Fig. 6.5: time1.h 2 // Declaration of the Time class. 3 // Member functions are defined in time1.cpp Dot ( . ) replaced with underscore ( _ ) in file name. 4 If time1.h (TIME1_H) is not defined (#ifndef) then it is loaded (#defineTIME1_H). If TIME1_His already defined, then everything up to #endifis ignored. This prevents loading a header file multiple times. 5 // prevent multiple inclusions of header file 6 #ifndef TIME1_H 7 #define TIME1_H 8 9 // Time abstract data type definition 10 class Time { 11 public: 12 Time(); // constructor 13 void setTime( int, int, int ); // set hour, minute, second 14 void printMilitary(); // print military time format 15 void printStandard(); // print standard time format 16 private: 17 int hour; // 0 - 23 18 int minute; // 0 - 59 19 int second; // 0 - 59 20 }; 21 22 #endif 1. Using the same Time class as before, create a header file

  12. 23 // Fig. 6.5: time1.cpp 24 // Member function definitions for Time class. Source file uses #include to load the header file 25 #include <iostream> 26 27 using std::cout; 28 Source file contains function definitions 29 #include "time1.h" 30 31 // Time constructor initializes each data member to zero. 32 // Ensures all Time objects start in a consistent state. 33 Time::Time() { hour = minute = second = 0; } 34 35 // Set a new Time value using military time. Perform validity 36 // checks on the data values. Set invalid values to zero. 37 void Time::setTime( int h, int m, int s ) 38 { 39 hour = ( h >= 0 && h < 24 ) ? h : 0; 40 minute = ( m >= 0 && m < 60 ) ? m : 0; 41 second = ( s >= 0 && s < 60 ) ? s : 0; 42 } 43 44 // Print Time in military format 45 void Time::printMilitary() 46 { 47 cout << ( hour < 10 ? "0" : "" ) << hour << ":" 48 << ( minute < 10 ? "0" : "" ) << minute; 49 } 50 51 // Print time in standard format 52 void Time::printStandard() 53 { 54 cout << ( ( hour == 0 || hour == 12 ) ? 12 : hour % 12 ) 55 << ":" << ( minute < 10 ? "0" : "" ) << minute 56 << ":" << ( second < 10 ? "0" : "" ) << second 57 << ( hour < 12 ? " AM" : " PM" ); 58 } 2. Create a source code file2.1 Load the header file to get the class definitions2.2. Define the member functions of the class

More Related