What does this code mean?

Question

int* ptr = new int(27);
*ptr = 34;
...
delete ptr;

Answer 1

int* ptr = new int(27);
dynamically allocate memory on the heap. (27) means it is initialized with 27.
Be aware that [27] and (27) are different. [27] would mean an uninitialized array with 27 elements.

So ptr points somewhere on the heap and that memory location contains the value 27.

*ptr = 34;
Assign 34 to the memory location pointed to by ptr.

delete ptr;
The memory on the heap is no longer needed and is deallocated. ptr no longer owns the memory.

Note that delete[] would be used if ptr was pointing to an array.