Question

I am trying to make a new array in my project

the code is:

#include <iostream>
using namespace std;
void makeArray( int *& arrayPtr, int size );
int main( )
{
  int * arrPtr;
  int size =10;
  makeArray( arrPtr, size );
  for(int j=0;j<size;j++)
  {
    cout<<arrPtr[j]<<endl;
  }
}
void makeArray( int *& arrayPtr, int size )
{
  int arr[size-1];
  for(int i=0;i<size;i++)
  {
    arr[i]=0;
  }

  *&arrayPtr=*&arr;
}

According to the requirements i need to use the above “makeArray” method inorder to make the array.
When i run the code the output is garbage values not zero…..

any help will be appreciated

thank you

Answer 1

The way you are creating the array is on the stack, which means that it will not exist after the makeArray function finishes.

You will need to allocate the array on the heap.

So:

int arr[size-1];

should be:

int *arr = new int[size-1];

Also, I think you mean to do this in makeArray():

arrayPtr = arr;

Instead of:

*&arrayPtr=*&arr;

Which compiles but is more complex and is functionally the same thing in this context.

But you may prefer just returning an int* instead of taking a reference to the pointer.

Then when you are done using the array in main(), and set it to NULL just in case you accidentally use it again, like this:

for(int j=0;j<size;j++)
{
  cout<<arrPtr[j]<<endl;
}
delete [] arrPtr;
arrPtr = NULL;