Thread: why am i getting linker errors?

The following is a class I built. Compiling the cpp file I get NO errors. But when I build the .h file and .cpp file, I always get these 2 linker errors and I'm not sure why. I followed the step by step process of creating a project workspace using the Microsoft visual C++ compiler and made sure both files were inserted into that workspace. So if anyone could tell me why I'm getting linker errors, I'd really appreciate it. Thanks so much.

Code:

   
#define MAX_SIZE 20


class List
{
public:
  List(); //starts list


   //member functions
int Insert(int);//inserts a number at the end(if there is room)
int Insert(int, int);//if room and if valid position given, inserts value 
                    //in middle
int Delete(int);//if given a position, deletes a value from list
int Size();//returns list size
int Sum(); //returns values' sum in list
float Average();//returns values' in list
int Evens();// returns how many even numbers in list after counting up
int Greater(int);//returns how many numbers are greater than a //given parameter value after counting up
int WhereIs(int);//gives position of first occurence of a value, if not  //found then 0 is returned
int Smallest();//returns list's smallest value
void Clear();//resets list object to represent an empty list
void Show();//shows the contents of the list

private:
void CalculateSum(void);
int arr[MAX_SIZE];//size can be at most 20 integers
int sum;
int size;


};

Code:

//This file contains the declarations of the list header//


#include <iostream>
#include "list.h"

using namespace std;

//List member functions

List::List()
//gives user an empty list, 
{

Clear();//clears list for inserting

}//end of constructor

int List::Insert (int value)
{

   if (size<MAX_SIZE) {    //determines if size is less than 20

   
   arr[size++]=value;
   CalculateSum();
   return 1;


                       }
   cout<<"*** Invalid List Position Number\n";
   return 0;
}


int List::Insert (int pos, int value)
{
   
   if ((pos>0) && (pos < size) && (size<MAX_SIZE)) {

   
   for (int i=size;i>pos-1;i--) //loop
       arr[i]=arr[i-1];

   arr[pos-1]=value;


   size++;
   CalculateSum();

   return 1;


                                                   }
   cout<<"*** Invalid List Position Number\n";
   return 0;

}


int List::Delete (int pos)
{
   
   if ((pos>0) && (pos < size)) {  //determines if position is greater  
  
                                                   //than 0 and less than size
   
   
     for (int i=pos-1;i<size;i++) //loop
           arr[i]=arr[i+1];

       


       size--;
       CalculateSum();
       
       return 1;

                                }
   cout<<"*** Invalid List Position Number\n";

   return 0;
}



int List::Size (void) {    //returns size of list
   return size;
                      }

float List::Average (void) {   //returns average of list
   return sum/size;
                           }

int List::Evens (void) {
   int e=0;

   
   for (int i=0;i<size;i++) //loop
       if ((arr[i] % 2) == 0) //test for even
           e++;//increment evens

   return e;
                        }

int List::Greater(int x) {
   int g=0;

   
   for (int i=0;i<size;i++) //loop
       if (arr[i]>x) //test for greater than
           g++;//increment greater

   return g;
                         }


int List::Smallest (void) {
   int s=32767;

   
   for (int i=0;i<size;i++) //loop
       if (arr[i]<s) //test if arr[i] is smaller than s
           s=arr[i]; //set s to arr[i]


   return s;
                          }


int List::WhereIs(int x) {

   for (int i=0;i<size;i++) //loop
     if (arr[i]==x)   //test if arr[i] is equal to x
         return i+1;

    return 0;

                         }



void List::CalculateSum(void) {

   //zero out sum
   sum=0;

   //add all the numbers together
   for (int i=0;i<size;i++) 
       sum+=arr[i];

                              }


int List::Sum(void) {   //returning sum of list
   return sum;
                    }


   
void List::Clear(void) {
   //clears the array element by element
   //set all to zero
   for (int i=0;i<MAX_SIZE;i++) 
       arr[i]=0;

   //reset the size
   size=0;

                       }

void List::Show(void) {   //displaying contents of list

   cout << "Contents: ";

   for (int i=0;i<size;i++) 
       cout << arr[i] << ", ";

   cout << "\n";



                      }

Thanks a lot guys.