The solution to Implement a circular buffer of size N

额，拖了好久，都没时间做~一开始想成用数组实现没有看清楚题目啊。

链表操作就是要画出来，写的时候细心点，特别是注意之前的变量有没有改变，要加个临时变量来存。

链表易于插入，删除。数组是随机访问。把两者结合起来用就更好。

  1 #include <iostream>

  2 #include <string>

  3 

  4 using namespace std;

  5 

  6 typedef unsigned int UINT;

  7 typedef struct SingleNode

  8 {

  9     SingleNode():next(NULL){}

 10     string data;

 11     SingleNode * next;

 12 }SingleNode;

 13 

 14 class CircularBuffer

 15 {

 16 public:

 17     CircularBuffer(UINT size):m_nBufferSize(size),m_nCurrentSize(0)

 18     {

 19         m_pHead = new SingleNode();

 20         m_pTail = m_pHead;

 21     }

 22     ~CircularBuffer(){ Release();}

 23 public:

 24     bool Append(UINT num);

 25     bool Remove(UINT num);

 26     bool List();

 27 private:

 28     bool IsFull();

 29     bool IsEmpty();

 30     bool Release();

 31 private:

 32     UINT m_nBufferSize;

 33     UINT m_nCurrentSize;

 34     SingleNode * m_pHead;

 35     SingleNode * m_pTail;

 36 };

 37 //

 38 bool CircularBuffer::IsFull()

 39 {

 40     return m_nCurrentSize >= m_nBufferSize;

 41 }

 42 bool CircularBuffer::IsEmpty()

 43 {

 44     return !m_nCurrentSize;

 45 }

 46 bool CircularBuffer::Release()

 47 {

 48     if(NULL == m_pHead || NULL == m_pHead->next)

 49         return true;

 50     SingleNode * currentNode = m_pHead->next, *tempNode = NULL;

 51     while(m_pHead != currentNode)

 52     {

 53         tempNode = currentNode->next;

 54         delete currentNode;

 55         currentNode = tempNode;

 56     }

 57     return true;

 58 }

 59 bool CircularBuffer::Append(UINT num)

 60 {

 61     for(int i = 0; i < num; i++)

 62     {

 63         SingleNode * newNode = new SingleNode();

 64         cin >> newNode->data;

 65         m_pTail->next = newNode;

 66         m_pTail       = newNode;

 67         m_pTail->next = m_pHead;

 68         if(IsFull())

 69         {

 70             SingleNode * tempNode = m_pHead->next;

 71             m_pHead->next = tempNode->next;

 72             delete tempNode;

 73         }

 74         else m_nCurrentSize ++;

 75     }

 76     return true;

 77 }

 78 bool CircularBuffer::Remove(UINT num)

 79 {

 80     SingleNode * tempNode;

 81     for(int i = 0; i < num; i++)

 82     {

 83         tempNode = m_pHead->next;

 84         if(m_pHead == tempNode) break;

 85         m_pHead->next = tempNode->next;

 86         delete tempNode;

 87         m_nCurrentSize --;

 88     }

 89     if(IsEmpty())

 90     {

 91         m_pHead->next = NULL;

 92         m_pTail = m_pHead;

 93     }

 94     return true;

 95 }

 96 bool CircularBuffer::List()

 97 {

 98     if(NULL == m_pHead || NULL == m_pHead->next)

 99         return true;

100     SingleNode * tempNode = m_pHead->next;

101     while(m_pHead != tempNode)

102     {

103         cout << tempNode->data << endl;

104         tempNode = tempNode->next;

105     }

106     return true;

107 }

108 void parseCmd(CircularBuffer&cb)

109 {

110     char cmd;

111     UINT pram;

112     while(cin >> cmd)

113     {

114         switch(cmd)

115         {

116         case 'A':

117             cin >> pram;

118             cb.Append(pram);

119             break;

120         case 'R':

121             cin >> pram;

122             cb.Remove(pram);

123             break;

124         case 'L':

125             cb.List();

126             break;

127         case 'Q':

128             return;

129         default:break;

130         }

131     }    

132 }

133 int main()

134 {

135     UINT size;

136     while(cin >> size)

137     {

138         CircularBuffer cb(size);

139         parseCmd(cb);

140     }

141     return 0;

142 }