• gistfile1.txt

#include <cstdlib>
#include <iostream>
#include <string>

using namespace std;

int hash_string(char str_name[]);

int main()
{
	int pass, slen, spos, hash_value;
	char hash_str[9];
	char hash_table[64][9];
	int collisions = 0;

	// init hash table
	for ( pass = 0; pass < 64; pass++)
	{
		hash_table [ pass ][0] = '\0';
	}

	// porudce 64 strings to be hashed
	for ( pass = 0; pass < 64; pass ++)
	{
		// generate random string of 5 to 8 chars
		slen = 5 + rand() % 4;
		spos = 0;
		do
		{
			hash_str[ spos ] = 'A' + rand() % 25;
			spos++;
			slen--;
		} while ( slen != 0 );
		hash_str[ spos ] = '\0';
		
    //display the string and its hash value
    if ( 0 == pass % 4 )
    {
      cout << endl;
    }
    cout << hash_str << ", " ;
		hash_value = hash_string ( hash_str );
    cout << hash_value << "\t";

    // check for collision
    if ( '\0' == hash_table[ hash_value ] [0] )
    {
      strcpy( hash_table[ hash_value ], hash_str );
    } else {
      collisions++;
    }
	
  }
  cout << endl;
  cout << "There were " << collisions < " collisions. " << endl;

  return EXIT_SUCCESS;
}

int hash_string(char str_name[])
{
  int hashval;

  hashval = str_name[ 0 ];
  hashval ^= str_name[ strlen( str_name ) / 2 ];
  hashval += str_name[ strlen( str_name ) - 1 ];
  return ( hashval & 0x3f );
}