what is the output of program

Question

#include<iostream>
using namespace std;

int main()
{
  int *arr ;

   arr = new int[10];
  for(int i=0;i<10;i++)
        arr[i] = i;

    delete arr;
    for(int i=1 ; i<10;i++)
cout<<arr[i];

}

I was expecting a answer "123456789", but the answer was "023456789"

Answer 1

Two problems here: you are deleting the array before using it, which results in undefined behavior.

Second, you are not using the correct form of delete, which is probably why only the first element is cleared.

The delete needs to be moved to after the print loop, and it needs to be changed to:

delete [] arr;

Answer 2

#include<iostream>
using namespace std;
int main()
{
  int *arr ;
   arr = new int[10];
  for(int i=0;i<10;i++)
        arr[i] = i;

    for(int i=1 ; i<10;i++)
    cout<<arr[i];
    delete [] arr;

}