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POHashTable (search function)
primarykey
Id
15768561
data
AcceptedAnswerId
15769323
AnswerCount
1
ClosedDate
2013-04-03T03:45:53.380
CommentCount
14
CommunityOwnedDate
CreationDate
2013-04-02T15:51:43.290
FavoriteCount
0
LastActivityDate
2013-04-02T16:28:08.583
LastEditDate
2013-04-02T16:24:28.190
LastEditorUserId
1777067
OwnerUserId
1777067
ParentId
0
PostTypeId
1
Score
-2
ViewCount
5223
LastEditorDisplayName
text
Body
<pre><code>#include <iostream> #include <cstring> #include <vector> #include "list.cpp" #include <cmath> using namespace std; struct HashEntry{ int key; List<string> list; HashEntry(int k) { key=k; } }; class Hash{ private: HashEntry *Table[100]; int a; public: Hash(int A); void insert(string word); void Lookup(string word); }; Hash::Hash(int A) { a=A; } void Hash::insert(string word) { int c=0; for (int i=0;i<word.size();i++) { int b=(int)((a^i)*(word[i])); c+=b; } c%=100; List<string> list; if (Table[c-1]==NULL) //if the respective bucket doesnot have any string Table[c-1]=new HashEntry(c-1); Table[c-1]->list.insertAtTail(word); } void Hash::Lookup(string word) { int c=0; for (int i=0;i<word.size();i++) { int b=(int)((a^i)*(word[i])); c+=b; } cout<<"one"<<endl; c%=100; Table[c-1]->list.searchFor(word); cout<<"two"<<endl; } </code></pre> <p>I am making a hash table using seperate chaining taking.my hash function is making a polynomial equation using a constant 'a' whose power is increasing with the index of the letter in a word.(a^0xb+a^1xb+a^2xb+...) , where b is a letter in the word which is being hashed and then I take mod(100) of the final answer.The problem i am facing is in lookup function.when I test the lookup function,the searchFor() function which is in part of part Linked list class does not work although it works fine on its own and i get an segmentation fault after the cout<<"one" which i used to debug .I am sorry for bothering but I just can't understand the problem here.The linked list class file is below.I am just pasting the function in which i am having problem</p> <pre><code>#ifndef __LIST_H #define __LIST_H #include <cstdlib> #include <iostream> #include <vector> using namespace std; /* This class just holds a single data item. */ template <class T> struct ListItem { vector<string> words; T value; ListItem<T> *next; ListItem<T> *prev; ListItem(T theVal) { this->value = theVal; this->next = NULL; this->prev = NULL; } }; /* This is the generic List class */ template <class T> class List { ListItem<T> *head; public: // Constructor List(); // Copy Constructor List(const List<T>& otherList); // Destructor ~List(); // Insertion Functions void insertAtHead(T item); void insertAtTail(T item); void insertAfter(T toInsert, T afterWhat); void insertSorted(T item); void printList(); // Lookup Functions ListItem<T> *getHead(); ListItem<T> *getTail(); void *searchFor(T item); // Deletion Functions void deleteElement(T item); void deleteHead(); void deleteTail(); // Utility Functions int length(); }; #endif template <class T> void List<T>::searchFor(T item) { ListItem<T> *temp=head; if (temp!=NULL) { while (temp->next!=NULL) { T sample=temp->value; if (sample==item) { cout<<"String found"; return; } temp=temp->next; } T s=temp->value; if (s==item) { cout<<"String found"; return; } } } </code></pre>
Tags
<c++>
Title
HashTable (search function)
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PostAcceptedAnswerId
1. PO
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PostParentId
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PostTypePostTypeId
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UserLastEditorUserId
1. USdigi_exp527
UserOwnerUserId
1. USdigi_exp527
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PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. This table or related slice is empty.
PostsParentIdCreationDate
1. PO
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1. VO
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2. VO
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