Dynamic Array assignment question

[Agent1291]

Alright so I've got another question on this program I'm writing. The assignment we were give was...

"An array can be used to store large integers one digit at a time. For example, the integer 1234 could be stored in the array a by setting a[0] to 1, a[1] to 2, a[2] to 3, and a[3] to 4. However, for this assignment, you may find it easier to store the digits backward, that is, place 4 in a[0], place 3 in a[1], place 2 in a[2], and place 1 in a[3]. Design, implement and test a class in which each object is a large integer with each digit stored in a separate element of an array. You will also need a private member variable to keep track of the sign of the integer (perhaps a boolean variable). The number of digits may grow as the program runs, so the class must use a dynamic array. "

I can honestly say I am stumped as to how to make this work. Here is my code. thanks in advance for any help.

#include <iostream>
using namespace std;


class largenum
{
      public:
             void enternum(int numdigits);
             void enterdigits(int x, int numdigits, int digit[]);
             void displargenum(int x, int digit []);
             
             };




int main()
{

          largenum newnum;
          int numdigits, x, digit[x];
        
                newnum.enternum(numdigits);
                newnum.enterdigits(x, numdigits, digit[x]);
                newnum.displargenum(x, digit [x]);

                system("pause");
                
                return 0;


     }

//functions

void largenum::enternum(int numdigits)
{

     cout << "Enter the number of digits in your number: ";
     cin >> numdigits;

     int *digit = new int[numdigits];
     
     }

void largenum::enterdigits(int x, int numdigits, int digit[x])
{
     for(x = 0; x < numdigits; x++)
     {
          cout << "Enter a digit: ";
          cin digit[x];
          }
          
          }
          
void largenum::displargenum(int x, int digit [])
{
     cout << "Your number is " << digit[x];
     
     delete []digit;
     
     }