C++ 实现哈希表的实例

该散列表的散列函数采用了除法散列函数、乘法散列函数、全域散列函数，每一个槽都是使用有序单向链表实现。

实现代码：

LinkNode.h

#include<iostream> using namespace std; class Link; class LinkNode { private: int key; LinkNode* next; friend Link; public: LinkNode():key(-1),next(NULL){} LinkNode(int num):key(num),next(NULL){} int Getkey() { return key; } };

Link.h

#include"LinkNode.h" class Hash; class Link { private: friend Hash; LinkNode* head; int length; public: Link():head(NULL),length(0) {} Link(LinkNode* node):head(node) { length+=1; } ~Link() { MakeEmpty(); } void MakeEmpty() { if(head==NULL) return ; LinkNode* p=head; while(p) { head=head->next; delete p; p=head; } } int GetLength() { return length; } void Insert(int num) { length++; LinkNode* p=new LinkNode(num); if(head==NULL) { head=p; return ; } LinkNode* q=head,*t=head->next; if(q->key>num) { head=p; head->next=q; return ; } while(t) { if(t->key>=num) { q->next=p; p->next=t; return ; } else { q=t; t=t->next; } } q->next=p; } bool Delete(int num) { if(head==NULL) { cout<<"the link is empty!"<<endl; return 0; } LinkNode* p=head,*t=head->next; if(p->key==num) { head=head->next; delete p; length--; return 1; } while(t) { if(t->key==num) { p->next=t->next; delete t; length--; return 1; } else if(t->key<num) { p=t; t=t->next; } } return 0; } int Search(int num) { LinkNode* p=head; while(p) { if(p->key==num) { return num; } else if(p->key<num) { p=p->next; } else { return 0; } } return 0; } bool IsEmpty() { if(head==NULL) { return 1; } else return 0; } void Print(int num) { if(head==NULL) { cout<<"the"<<num<<"th link is null!"<<endl; } LinkNode* p=head; while(p) { cout<<p->key<<" "; p=p->next; } cout<<endl; } };

Hash.h

Hash表中每一个元素存储一个链表

#include"Link.h" class Hash { private: Link*Table; public: Hash(int num):Table(new Link [num]){} ~Hash() { delete [] Table; } //除法散列法 int H1(int num,int m) { return num%m; } //乘法散列法 int H2(int num,float A,int m) { float fnum=(float)num; float re=((fnum*A)-(int)(fnum*A))*m; return (int)re; } //全域散列 int H3(int num,int p,int m) { int a,b; a=rand()%p; b=rand()%p; return ((a*num+b)%p)%m; } void Insert(int num,int n) { int key; if(n==1) { key=H1(num,17); } else if(n==2) { key=H2(num,0.618033,17); } else { key=H3(num,701,17); } Table[key].Insert(num); } bool Delete(int num,int n) { int key; if(n==1) { key=H1(num,17); } else if(n==2) { key=H2(num,0.618033,17); } else { key=H3(num,701,17); } return Table[key].Delete(num); } int Search(int num,int n) { int key; if(n==1) { key=H1(num,17); } else if(n==2) { key=H2(num,0.618033,17); } else { key=H3(num,701,17); } if(Table[key].Search(num)!=0) { return key+1; } else return -1; } void Print(int num) { int i; for(i=0;i<num;i++) { if(Table[i].IsEmpty()) continue; Table[i].Print(i); } } };

main.h

#include"Hash.h" int main() { Hash hash(1000),ha(100),sh(100); int a[15]={15,6,9,4,7,32,569,419,78,125,635,46,456,16,457}; int i; for(i=0;i<15;i++) { hash.Insert(a[i],1); } for(i=0;i<15;i++) { ha.Insert(a[i],2); } cout<<endl; for(i=0;i<15;i++) { sh.Insert(a[i],3); } hash.Print(1000); cout<<endl; ha.Print(100); cout<<endl; sh.Print(100); cout<<endl; cout<<hash.Search(46,1)<<endl; if(hash.Delete(125,1)) { cout<<hash.Search(125,1)<<endl; } }

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