Thread: Error when trying to implement a hash table class

Hello again,

I started writing a few lines of code and caught myself think 'Wow, hash tables are pretty nice, easy to write (havn't attacked index collision yet though.) and generally very cool stuff.' I hit a small snag though. First here's the code:

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

class hashTable {
	protected:
		char **table;
		
		int keys;
		//int **keysTable;
		
		unsigned int GenerateHash(char *string);
		
	public:
		hashTable() {
			keys = 0;
		}
	
		int Insert(char *key, char *value);
		
		char *operator[] (char *);
};

char *hashTable::operator[] (char *key) {
	return table[GenerateHash(key)];
}

int hashTable::Insert(char *key, char *value) {
	int strSize = strlen(value);
	unsigned int hash = GenerateHash(key);
	
	table[hash] = (char *)malloc(sizeof(char) * strSize);
	strcpy(table[hash], value);
	
	//keysTable[keys] = (int *)malloc(sizeof(int));
	//*keysTable[keys] = hash;
	keys++;
	
	return hash;
}

unsigned int hashTable::GenerateHash(char *key) {
	unsigned int hash = 0;
	int size = strlen(key);
	
	for (int i = 1; i < size; i++) {
		hash += (key[i] &#37; 251) * i;
	}
		
	return hash;
}

int main() {
	hashTable table;
	int hash = table.Insert("key", "testing");
	
	printf("%s:%i = %s\n", "key", hash, table["key"]);
	
	return 0;
}

As soon as I uncomment 'int **keysTable' the program segfaults when I try to run it. If I uncomment that line and comment the 'int keys' line instead it dosn't segfault (uncommenting/commenting lines that depent on the variable).

And I can't for the life of me figure out where the problem lies.

well, to begin with, neither 'keysTable' nor 'table' have been allocated any memory.

hash_value % table_size