Question 4: implement class methods [8]

Suppose we are provided with the class definition shown below: 
class IntArr {
   public:
      IntArr();                   // Note: initially the array is NULL
      ~IntArr();                  // deallocates the array
      bool Alloc(int N, int v);   // allocates an array of N integers,
                                  //    initializes the values to v
      int getSum();               // returns the sum of the array elements
      bool set(int v, int p);     // if p is valid this stores value v in 
                                  //      position p and returns true
                                  //   otherwise returns false
      bool lookup(int p, int &v); // if p is valid this sets v to the value 
                                  //   stored in position p and returns true
                                  // otherwise returns false
   private:
      int ArrSize;   // the size of the allocated array
      int *Arr;      // the allocated array
};
Provide implementations for both the Alloc and getSum methods of the class. 
Sample solution
bool IntArr::Alloc(int N, int v)
{
   if (Arr != NULL) {
      // deallocate old memory, just in case
      delete [] Arr;
   }
   // allocate new array and check it succeeds
   Arr = new int[N];
   if (Arr == NULL) {
      ArrSize = 0;
      return false;
   }
   // initialize new array
   for (int i = 0; i < ArrSize; i++) {
      Arr[i] = v;
   }
   return true;
}

int IntArr::getSum()
{
   if ((Arr == NULL) || (ArrSize < 1)) {
      return 0;
   }
   int sum = 0;
   for (int i = 0; i < ArrSize; i++) {
       sum += Arr[i];
   }
   return sum;
}