I have this program that is supposed to read part numbers from a text file.
101-110, 301-310, 501-510 and put them into a hash table. It will prompt for one of four algorithms to be used and then continue to load the part numbers. Everything seems to be working okay, but it seems to repeat the last part number 510. Is there something that I need to put at the end of the text file to indicate it is the end of file and to stop. Please be nice - I am just a beginner - had to do quite a bit of reading to get this far
Any suggestions are appreciated.

C++ Syntax (Toggle Plain Text)

#include <iostream.h>
#include <fstream.h>
#include <stdio.h>
 
 
//function declaration
int HashAddress (int PartNumber, char Algorithm);
 
// global variables
int array[41];
 
int main()
{
 
  int i = 0;
  int max_read = 41;
  int amountRead = 0;
  int PartNumber, Index;
  char Algorithm;
 
  // set array elements to -1
  for(i = 0; i < 41; i++)
  {
 
  	array[i] = -1;
 
  }  
 
  std::ifstream inputfile("part.txt",std::ios::in |std::ios::binary);
 
  if(!inputfile)
  {
 
    std::cout<<"Could not open file"<<std::endl;
    return 1;
 
  }
 // prompt for input from user to choose algorithm
 
	cout<<"Please select Algorithm\n";
	cout<<"1. Modulo Division using linear probing \n";
	cout<<"2. Modulo Division using key offset \n";
	cout<<"3. PsuedoRandom using linear probing \n";
	cout<<"4. Rotation using linear probing \n";
	cin >> Algorithm;
 
 
 
  //this is where we are reading in the information into our array
  for(i = 0; i < 41; i++)
  {
 
    // as you read each part number in the file
    inputfile >>  PartNumber;
 
	// HashAddress function returns array index and it is assigned to variable Index
	Index = HashAddress(PartNumber,Algorithm); 
 
	// put part number in array 
	array[Index] = PartNumber;
 
  }
 
  return 0; 
 
}	 
 
// function HashAddress returns location for hash table
int HashAddress(int PartNumber, char Algorithm)
{
 
  int Index, count;  
  int x, y, z;
 
 
  // use algorithms to hash address
  switch(Algorithm)
  {
  case '1': // first algorithm, Modulo Division with linear probing
   Index = PartNumber % 41;  
 
 
  break;
 
  case '2': // second algorithm, Modulo Division with key offset
   Index = PartNumber % 41;  
 
  break;
 
  case '3':  // third algorithm, Psuedorandom with linear probing
  Index = (17 * PartNumber + 7) % 41;
 
  break;
 
  case '4':  // fourth algorithm, Rotation with linear probing
  x = PartNumber % 10;
  y = PartNumber / 10;
  z = x * 10;
  Index = (z+y) % 41; 
 
  break;
 
  default:
  cout << "Invalid Selection\n"; //invalid choice 
  }  
 
   cout << "\nPart Number: " << " " << PartNumber << " " << "Index: " << Index;
 
  // check to see if array element is occupied 
  if(array[Index] < 0)
 
	 // array element is available so return the address/location
	 return Index;
 
  else //collision, part number is already in that spot
    {
        count = 0; // use count to stop if table is full
 
        do 
        {  
 
             switch(Algorithm)
             {
			 case '1':
	 	 	 Index = (Index + 1) % 41; // % 41 allows for wrap around
			 break;
 
			 case '2':
 
             Index = (PartNumber / 41) % 41;			 
 
             case '3':
	 	 	 Index = (Index + 1) % 41; // % 41 allows for wrap around
			 break;
 
             case '4':
	 	 	 Index = (Index + 1) % 41; // % 41 allows for wrap around
			 break;
 
			 default:
			   cout << "Invalid Selection\n"; //invalid choice
             }  
             count ++; 
         }  while ((array[Index] > 0) && (count < 41)); 
 
 
 
 
        if (count == 41)
        {    
			//print ERROR hash table is full
           cout << "Hash table is full. Can not insert part number.";
		}	           
		else 
			 cout << "\nCollision count:" << " " << count << " "<< "New Index:" << " " << Index;
 
		   return Index;
 
    }
 
 
 
}

#include <iostream.h> #include <fstream.h> #include <stdio.h> //function declaration int HashAddress (int PartNumber, char Algorithm); // global variables int array[41]; int main() { int i = 0; int max_read = 41; int amountRead = 0; int PartNumber, Index; char Algorithm; // set array elements to -1 for(i = 0; i < 41; i++) { array[i] = -1; } std::ifstream inputfile("part.txt",std::ios::in |std::ios::binary); if(!inputfile) { std::cout<<"Could not open file"<<std::endl; return 1; } // prompt for input from user to choose algorithm cout<<"Please select Algorithm\n"; cout<<"1. Modulo Division using linear probing \n"; cout<<"2. Modulo Division using key offset \n"; cout<<"3. PsuedoRandom using linear probing \n"; cout<<"4. Rotation using linear probing \n"; cin >> Algorithm; //this is where we are reading in the information into our array for(i = 0; i < 41; i++) { // as you read each part number in the file inputfile >> PartNumber; // HashAddress function returns array index and it is assigned to variable Index Index = HashAddress(PartNumber,Algorithm); // put part number in array array[Index] = PartNumber; } return 0; } // function HashAddress returns location for hash table int HashAddress(int PartNumber, char Algorithm) { int Index, count; int x, y, z; // use algorithms to hash address switch(Algorithm) { case '1': // first algorithm, Modulo Division with linear probing Index = PartNumber % 41; break; case '2': // second algorithm, Modulo Division with key offset Index = PartNumber % 41; break; case '3': // third algorithm, Psuedorandom with linear probing Index = (17 * PartNumber + 7) % 41; break; case '4': // fourth algorithm, Rotation with linear probing x = PartNumber % 10; y = PartNumber / 10; z = x * 10; Index = (z+y) % 41; break; default: cout << "Invalid Selection\n"; //invalid choice } cout << "\nPart Number: " << " " << PartNumber << " " << "Index: " << Index; // check to see if array element is occupied if(array[Index] < 0) // array element is available so return the address/location return Index; else //collision, part number is already in that spot { count = 0; // use count to stop if table is full do { switch(Algorithm) { case '1': Index = (Index + 1) % 41; // % 41 allows for wrap around break; case '2': Index = (PartNumber / 41) % 41; case '3': Index = (Index + 1) % 41; // % 41 allows for wrap around break; case '4': Index = (Index + 1) % 41; // % 41 allows for wrap around break; default: cout << "Invalid Selection\n"; //invalid choice } count ++; } while ((array[Index] > 0) && (count < 41)); if (count == 41) { //print ERROR hash table is full cout << "Hash table is full. Can not insert part number."; } else cout << "\nCollision count:" << " " << count << " "<< "New Index:" << " " << Index; return Index; } }