1IDLOOPC1998.

Object-Oriented Programming

Using C++

CLASS 17

2IDLOOPC1998.

� Change a type specific Array class to a template

Ob

ject

ives

3IDLOOPC1998.

#include <iostream.h>template <class T>class Array{ friend ostream &operator<<

(ostream &, const Array &);friend istream &operator>> (istream &, Array &);

Fig. 8.4, Pg. 474

4IDLOOPC1998.

#include <iostream.h>template <class T>class Array{ friend ostream &operator<<

(ostream &, const Array<T> &);friend istream &operator>> (istream &, Array<T> &);

Fig. 8.4, Pg. 474

5IDLOOPC1998.

public:Array(int = 10);Array(const Array&);~Array( );int getSize( ) const;const Array &operator=(const Array &);bool operator= = ( const Array & ) const;bool operator!= ( const Array &right) const

{ return ! ( *this == right ); }int & operator[ ] ( int );const int &operator[ ] ( int ) const;static int getArrayCount ( );

Fig. 8.4, Pg. 474

6IDLOOPC1998.

public:Array(int = 10);Array(const Array<T> &);~Array( );int getSize( ) const;const Array<T> &operator= (const Array<T> &);bool operator==(const Array<T> &right) const;bool operator! =(const Array<T> &) const;{ return ! ( *this == right ); }

T &operator[]( int );const T &operator[] ( int ) const; static int getArrayCount( );

Fig. 8.4, Pg. 474

7IDLOOPC1998.

private:int *ptr;int size;static int arrayCount;

};

Fig. 8.4, Pg. 474

8IDLOOPC1998.

private:T *ptr;int size;static int arrayCount;

};

Fig. 8.4, Pg. 474

9IDLOOPC1998.

// Initialize static data member at file scope

int Array::arrayCount = 0;

Fig. 8.4, Pg. 475

10IDLOOPC1998.

// Initialize static data member at file scope

int Array<T>::arrayCount = 0;

Fig. 8.4, Pg. 475

11IDLOOPC1998.

Array::Array(int arraySize){

size = ( arraySize > 0 ? arraySize : 10);ptr = new int[ size ];assert( ptr ! = 0 );++arrayCount;

for ( int i - 0; i < size; i++ )ptr[ i ] = 0;

}

Fig. 8.4, Pg. 475

12IDLOOPC1998.

Fig. 8.4, Pg. 475

Array<T>::Array(int arraySize){

size = ( arraySize > 0 ? arraySize : 10);ptr = new T [ size ];assert( ptr ! = 0 );++arrayCount;

for ( int i - 0; i < size; i++ )ptr[ i ] = 0;

}

13IDLOOPC1998.

Array::Array(const Array &init):size( init.size){

ptr = new int[ size ];assert( ptr != 0 );++arrayCount;

for ( int i = 0; i < size; i++ )ptr[ i ] = init.ptr[ i ];

}

Fig. 8.4, Pg. 475

14IDLOOPC1998.

Fig. 8.4, Pg. 475

Array<T>::Array(const Array <T>&init):size( init.size)

{ptr = new T[ size ];assert( ptr != 0 );++arrayCount;

for ( int i = 0; i < size; i++ )ptr[ i ] = init.ptr[ i ];

}

15IDLOOPC1998.

Array::~Array( ){

--arrayCount;delete [ ] ptr;

}// Get the size of the arrayint Array::getSize( ) const{

return size;}

Fig. 8.4, Pg. 475

16IDLOOPC1998.

Array<T>::~Array( ){

--arrayCount;delete [ ] ptr;

}// Get the size of the arrayint Array<T>::getSize( ) const{

return size;}

Fig. 8.4, Pg. 475

17IDLOOPC1998.

//Overloaded assignment operatorconst Array &Array::operator

=(const Array &right) {if ( size != right.size ) {delete [ ] ptr;size = right.size;ptr = new int[ size ];assert( ptr ! = 0 );

}for (int i = 0; i < size; i++) ptr[ i ] = right.ptr[ i ]; }return *this;

}

Fig. 8.4, Pg. 476

18IDLOOPC1998.

Fig. 8.4, Pg. 476

//Overloaded assignment operatorconst Array <T>&Array<T>::operator

=(const Array <T>&right) {if ( size != right.size ) {delete [ ] ptr;size = right.size;ptr = new T[ size ];assert( ptr ! = 0 );

}for (int i = 0; i < size; i++) ptr[ i ] = right.ptr[ i ]; }return *this;

}

19IDLOOPC1998.

int Array::operator==(constArray & right) const

{if (size != right.size)

return false;for (int i = 0; i < size; i++)

if (ptr[i] != right.ptr[i])return false;

return true;}

Fig. 8.4, Pg. 476

20IDLOOPC1998.

int Array<T>::operator==(constArray<T> & right) const

{if (size != right.size)

return false;for (int i = 0; i < size; i++)

if (ptr[i] != right.ptr[i])return false;

return true;}

Fig. 8.4, Pg. 476

21IDLOOPC1998.

const int &Array::operator[ ] (int subscript){

// check for subscript out of range errorassert(0<=subscript&&subscript<size);

return ptr[subscript];}

Fig. 8.4, Pg. 476

22IDLOOPC1998.

const T &Array<T>::operator[ ] (int subscript)

{// check for subscript out of range errorassert(0<=subscript&&subscript<size);

return ptr[subscript];}

Fig. 8.4, Pg. 476

23IDLOOPC1998.

int Array::getArrayCount( ) { return arrayCount; }

istream &operator>>(istream &input,Array &a)

}for (int i = 0; i < a.size; i++)

input >> a.ptr[i];return input;

}

Fig. 8.4, Pg. 477

24IDLOOPC1998.

int Array<T>::getArrayCount( ) { return arrayCount; }

istream &operator>>(istream &input,Array<T> &a)

}for (int i = 0; i < a.size; i++)

input >> a.ptr[i];return input;

}

Fig. 8.4, Pg. 477

25IDLOOPC1998.

ostream &operator<<(ostream &output, const Array &a)

{for (int i = 0; i < a.size; i++) {

output << a.ptr[i] << ‘ ‘;if ((i + 1) % 4 = = 0)

output << endl;}

if (i % 4 ! = 0)output << endl;

return output; }

Fig. 8.4, Pg. 477

26IDLOOPC1998.

ostream &operator<<(ostream &output, const Array<T> &a)

{for (int i = 0; i < a.size; i++) {

output << a.ptr[i] << ‘ ‘;if ((i + 1) % 4 = = 0)

output << endl;}

if (i % 4 ! = 0)output << endl;

return output; }

Fig. 8.4, Pg. 477

27IDLOOPC1998.

main ( ){

cout << “# of arrays instantiated =”<< Array::getArrayCount( );

Array integers1 (7), integers2;cout << “# of arrays instantiated =”

<< Array::getArrayCount( )<<endl << endl;

Fig. 8.4, Pg. 477

28IDLOOPC1998.

main ( ){

cout << “# of arrays instantiated =”<< Array<int>::getArrayCount( );

Array<int> integers1 (7), integers2;cout << “# of arrays instantiated =”

<< Array<int>::getArrayCount( )<<endl << endl;

Fig. 8.4, Pg. 477

29IDLOOPC1998.

Garage Stack Template

30IDLOOPC1998.

The SCRATCHEMUP parking garage contains a single lane that holds up to 10 cars. There is only a single entrance/exit to the garage at one end of the lane. If a customer arrives to pick up a car that is not nearest the exit, all cars blocking it’s path are moved out, the customer’s car is driven out, and the other cars are restored in the same order that they were in originally.

31IDLOOPC1998.

Write a program that processes a group of input lines. Each input line contains an ‘A’ for arrival or a ‘D’ for departure, and a license plate number. Cars are assumed to arrive and depart in the order specified by the input. The program should print a message whenever a car arrives or departs. When a car arrives, the message should specify whether or not there is room for the car in the garage. If there is no room, the car leaves without entering the garage.

32IDLOOPC1998.

GARAGE

121

33IDLOOPC1998.

GARAGE

121 333

34IDLOOPC1998.

GARAGE

121 333 297

35IDLOOPC1998.

GARAGE

121 333

297

36IDLOOPC1998.

GARAGE

121

333297

37IDLOOPC1998.

GARAGE

333297

38IDLOOPC1998.

GARAGE

333

297

39IDLOOPC1998.

GARAGE

333 297

40IDLOOPC1998.

Exercises

Page 665

41IDLOOPC1998.

Exercises

a) friend void f1 ( );

Page 665

42IDLOOPC1998.

Exercises

a) friend void f1 ( );

friend of all template classes instantiated

Page 665

43IDLOOPC1998.

Exercises

b) friend void f2(C1<T1> &);

Page 665

44IDLOOPC1998.

Exercises

b) friend void f2(C1<T1> &);

friends of only a friend of C1 <particular type>

Page 665

45IDLOOPC1998.

Exercises

c) friend void C2::f4( );

Page 665

46IDLOOPC1998.

Exercises

c) friend void C2::f4( );

f4 is part of C2 class a friend of all

Page 665

47IDLOOPC1998.

Exercises

d) friend void C3<T1>::f5 (C1<T1> &);

Page 665

48IDLOOPC1998.

Exercises

d) friend void C3<T1>::f5 (C1<T1> &);

f5 is part of C3 <particular type>only friend of C1 <particular type>

Page 665

49IDLOOPC1998.

Exercises

e) friend class C5;

Page 665

50IDLOOPC1998.

Exercises

e) friend class C5;

friend of all

Page 665

51IDLOOPC1998.

Exercises

f) friend class C6<T1>;

Page 665

52IDLOOPC1998.

Exercises

f) friend class C6<T1>;

friend of all members of class C6 <particular type>friends of class C1 <Particular type>

Page 665

53IDLOOPC1998.

Q & A