Thread: Newbie trying to figure out copy constructors

I am trying to figure out copy constructors for a dynamic array and I am definitely missing something. If I go into the copy constructor routine during debug, the values appear to be correct but they don't percolate up to the newly created object. I'll post a portion of the code below:

Code:

// include header files for the classes that are being used
#include "stdafx.h"       //NOTE:  THis reference must be added to all cpp files in Visual Studio Express 2013


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


using namespace std;
const int ARRAY_SIZE_DEFAULT = 32;

class vectorOfInt {

    public:
        vectorOfInt();            //A no-argument constructor that allocates a 32-element vector
        vectorOfInt(int size);    //A constructor that takes an initial size as the argument
        ~vectorOfInt();            //Destructor
        
        //vectorOfInt& operator= (const vectorOfInt& vec);
        vectorOfInt(const vectorOfInt& vec);
        
        int size();                // return length
        void pushback(int val);  // A method pushback that adds an element to the end of the array, resizing if necessary
        void pushfront(int val);  // A method pushfront that adds an element to the beginning of the array
        int getVal(int index);  //A method get, taking an index and returning the value at that index
        void setVal(int index, int val);  //A method set, that takes an index and a value, and sets the value at that index
        int& operator[](int index);        //assignment operator

    private:    //variables

        int *pa;                //Points to the array
        int length;                //The Number of Elements in an array
        int nextIndex;            //The Next Highest Index Value.  Head value

};

//Copy Constructor
vectorOfInt::vectorOfInt(const vectorOfInt& vec){

    int *panew;
    
    int len = vec.length;
    panew = new int[len];
    memcpy(panew, vec.pa, len);
    
}

//Constructor with User Input on size
vectorOfInt::vectorOfInt(int size){
    //!!!Check to see if size is appropriate value, i.e., > 0
    pa = new int[size];   //new provides memory to user-defined number of ints, which pa points to.
    //initialize array to zero.
    for (int x = 0; x < size; ++x)  { pa[x] = 0; }
    length = size;    //default array size
    nextIndex = 0;                    //nextIndex points to the first address
}//end 



int main(){

    int lena, lenb, lenc, i;

    vectorOfInt a(8);
    lena = a.size();

    for (i = 0; i < lena; ++i){
        a.setVal(i, i+10);
    }

    vectorOfInt c(a); //copy constructor test    
    lenc = c.size();
}

The size of c is 0. Values of a were not copied to c, although they appear to do so within the copy constructor routine.

You don't set any of the member variables to anything; at some point you should assign values to pa, length, and nextIndex in your constructor. (You know, like you did in your other constructor.)

Why not copy the whole array?

Code:

memcpy(pa, vec.pa, length*sizeof(int));

(The last item is the number of bytes, not the number of items, because memcpy has no idea what objects these things are.)

Thanks Tabstop, grumpy and iMalc. I copied this file over from another which did use <map> and simply forgot to delete the reference.