Unexpected output, someone explain.

Question

The code below explains my confusion with the output.

https://code.sololearn.com/cmY4t2acW6Hu/#cpp

How can I increment the pointer to move to the next block of the array?
Should I only use array element reference syntax "[]" to address the block of the pointer array.
So confusing..
An explain would be appreciated.
- D3F4U1T

Answer 1

Yes it does. Incrementing the pointer is permanent. As stated, before the second loop, it points to the first element after the original space, and square brackets are really only syntactic sugar for pointer arithmetics behind the scenes.
A call like
pInt[ 0 ]
is implemented as
*( pInt + 0 ), so likewise
pInt[ i ] <=> *( pInt + i )
is true. The access to an array starts at whereever the pointer points to, and since that is no longer the original first value, you get garbage values.
Fixed code is simple:
https://code.sololearn.com/c2ot2YsAi7g4/?ref=app

Answer 2

After the allocation, "pInt" points to the first element of the array. By incrementing it, you move it along the elements inside the array to the right, so after the first for-loop, it then points to the memory cell that comes first after your allocated space in memory. Thus accessing those elements will give you garbage values, because it is no longer the space you allocated and initialized earlier. So yes, in this case it would be much simpler to use square brackets to access the elements.

Answer 3

Shadow But that still doesn't explain why did I get garbage values because in second "for" I used square brackets.
I need more clarification.
Can you post the fixed version of my code.

Answer 4

Thanks Shadow!! I was never expecting pointers to work that way.