Hash table with pointer vector - c++

Question

I'm having some trouble with an assignment that requires creating a hash table using a vector of Entry (ADT created by the professor). The program compiles successfully but gdb gives me the error message "No stack." when I try debugging. I've traced the error to a call to my function search() in my function insert().
I'm not sure where the problem comes from but I think it either stems from the way I access the vector or how I tried to initialize it in the constructor.
My source code is below, my professor wrote the structure Entry and class HT as well as the functions main() and hashing() which cannot be edited although new functions can be added to the class. Even though those parts cannot be edited I included them here for reference.
Here's my header file assignment8.h:
#ifndef ASSIGNMENT8_H
#define ASSIGNMENT8_H
#include <vector>
#include <string>
struct Entry {
std::string key;
std::string description;
Entry() { key = "---"; }
};
class HT {
private:
std::vector<Entry>* hTable;
int table_size=11;
int item_count;
int hashing(const std::string&);
public:
HT();
HT(int size);
~HT();
bool insert(const Entry& e);
int search(const std::string& key);
bool remove(const std::string& s);
void print();
//Student-made member fucntions
void setsize(int size){table_size = size;}
void setItemCount(int ic){ic = item_count;}
int getItemCount(){return item_count;}
};
#endif
and my cc file assignment8.cc:
#include <iostream>
#include <string>
#include <vector>
#include <fstream>
#include "assignment8.h"
using namespace std;
Entry* get_entry(const string& line)
{
//Holder for string fragments
string strArr[3];
int index = 0;
//Split the string
for(unsigned int i = 0; i < line.length(); i++)
{
if(line[i] != ':')
strArr[index] += line[i];
else
index++;
}
Entry* newEntry = new Entry;
//Pass strings to newEntry
(*newEntry).key = strArr[1];
(*newEntry).description = strArr[2];
return newEntry;
}
string get_key(const string& line)
{
//Holder for string fragments
string strArr[2];
int index = 0;
//Split string
for(unsigned int i = 0; i < line.length(); i++)
{
if(line[i] != ':')
strArr[index] += line[i];
else
index++;
}
//Return item-key
return strArr[1];
}
//----HT----//
// key is in form of letter-letter-digit
// compute sum <-- ascii(pos1)+ascii(pos2)+ascii(pos3)
// compute sum%htable_size
int HT::hashing(const string& key) {
return ((int)key[0] + (int)key[1] + (int)key[2])%table_size;
}
//--Constructors
//Default Constructor
HT::HT(){}
//Constructor
HT::HT(int size)
{
//Initializations
if(!size)
size = 11;
setsize(size);
hTable = new vector<Entry>[table_size];
}
HT::~HT()
{
delete[] hTable;
}
int HT::search(const std::string& key)
{
//Look for unused slot
for(int i = 0; i < table_size; i++)
{
if((*hTable)[i].key == key)
return hashing(key);
}
return -1;
}
bool HT::insert(const Entry& e)
{
//Get e's key
string eKey = e.key;
//If it's full, print error message and return false
if(getItemCount() == table_size)
{
cout << "Hash table is full\n";
return false;
}
//Checks to see if key already exists
if(search(eKey) != -1)
{
cout << "Key already exists in table\n";
return false;
}
//If it does not already exist,
for(int i = 0; i < table_size; i++)
{
string iKey = (*hTable)[i].key;
cout << i << "iteration(s)"<< endl;
if(iKey == "---" || iKey == "+++")
{
//Compute hash key value and insert into position
(*hTable)[i] = e;
setItemCount(++item_count);
return true;
}
}
return false;
}
bool HT::remove(const std::string& s)
{
for(int i = 0; i < table_size; i++)
{
string iKey = (*hTable)[i].key;
if(iKey == s)
{
iKey = "+++";
setItemCount(--item_count);
return true;
}
}
return false;
}
void HT::print()
{
cout << "----Hash Table----" << endl;
for(int i = 0; i < table_size; i++)
{
cout << (*hTable)[i].key << " " << (*hTable)[i].description << endl;
}
cout << endl << "------------------" << endl;
}
int main(int argc, char** argv ) {
if ( argc < 2 ) {
cerr << "argument: file-name\n";
return 1;
}
HT ht;
ifstream infile(argv[1], ios::in);
string line;
infile >> line;
while ( !infile.eof() ) {
if ( line[0] == 'A' ) {
Entry* e = get_entry( line );
ht.insert( *e );
delete e;
}
else {
string key = get_key(line);
if ( line[0] == 'D' ) {
cout << "Removing " << key << "...\n";
bool removed = ht.remove( key );
if ( removed )
cout << key << " is removed successfully...\n\n";
else
cout << key << " does not exist, no key is removed...\n\n";
}
else if ( line[0] == 'S' ) {
int found = ht.search( key );
if ( found < 0 )
cout << key << " does not exist in the hash table ..." << endl << endl;
else
cout << key << " is found at table position " << found << endl << endl;
}
else if ( line[0] == 'P' ) {
cout << "\nDisplaying the table: " << endl;
ht.print();
}
else
cerr << "wrong input: " << line << endl;
}
infile >> line;
}
infile.close();
return 0;
}
Thank you for any help or advice! :)