Data Abstraction(Chapter 4 of Thinking in C++)

CppLib.h1structStash

2{

3intsize;

4intquantity;

5intnext;

6unsignedcharstorage;

7voidinitialize(intsize);

8voidcleanup();

9intadd(constvoidelement);

10void*fetch(intindex);

11intcount();

12voidinflate(intincrease);

13};

CppLib.cpp1#include"CppLib.h"

2#include<iostream>

3#include<cassert>

4usingnamespacestd;

5

6constintincrement=100;

7

8voidStash::initialize(intsize)

9{

10this->size=size;

11quantity=0;

12storage=0;

13next=0;

14}

15

16intStash::add(constvoidelement)

17{

18if(next>=quantity)

19{

20inflate(increment);

21}

22

23intstartBytes=nextsize;

24unsignedchare=(unsignedchar)element;

25for(inti=0; i<size; i++)

26{

27storage[startBytes+i]=e[i];

28}

29next++;

30return(next-1);

31}

32

33voidStash::fetch(intindex)

34{

35assert(0<=index);

36if(index>=next)

37{

38return0;

39}

40

41return&(storage[indexsize]);

42}

43

44intStash::count()

45{

46returnnext;

47}

48

49voidStash::inflate(intincrease)

50{

51assert(increase>0);

52intnewQuantity=quantity+increase;

53intnewBytes=newQuantitysize;

54intoldBytes=quantitysize;

55unsignedchar*b=newunsignedchar[newBytes];

56for(inti=0; i<oldBytes; i++)

57{

58b[i]=storage[i];

59}

60delete []storage;

61storage=b;

62quantity=newQuantity;

63}

64

65voidStash::cleanup()

66{

67if(storage!=0)

68{

69cout<<"freeeing storage"<<endl;

70delete []storage;

71}

72}

CppLibTest.cpp1#include"CppLib.h"

2#include<fstream>

3#include<iostream>

4#include<string>

5usingnamespacestd;

6

7intmain()

8{

9Stash intStash;

10intStash.initialize(sizeof(int));

11for(inti=0; i<100; i++)

12{

13intStash.add(&i);

14}

15

16for(intj=0; j<intStash.count(); j++)

17{

18cout<<"intStash.fetch("<<j<<") ="

19<<(int)intStash.fetch(j)<<endl;

20}

21

22Stash stringStash;

23constintbufsize=80;

24stringStash.initialize(sizeof(char)bufsize);

25ifstreamin("CppLibTest.cpp");

26stringline;

27while(getline(in, line))

28{

29stringStash.add(line.c_str());

30}

31

32intk=0;

33charcp;

34while((cp=(char*)stringStash.fetch(k++))!=0)

35{

36cout<<"stringStash.fetch("<<k<<") ="

37<<cp<<endl;

38}

39

40intStash.cleanup();

41stringStash.cleanup();

42cin.get();

43}

原文链接: https://www.cnblogs.com/zhtf2014/archive/2010/11/10/1873278.html

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