Pointers

Question 1

What do pointers do in C++

Answer 1

They point to a location in memory

Question 2

What is the ‘&’ character

Answer 2

The reference character; a variable with a leading ‘&’ provides the memory address of that variable

Question 3

How do you declare a pointer?

Answer 3

With the * character.
ex: int* var or int *var

Question 4

How do you assign stack memory to a pointer?

Answer 4

int var = 7;
int *point =&var;

Question 5

How is the * character used to dereference?

Answer 5

When put in front of a pointer, it will provide the value in that memory address.

Question 6

How do you reassign the value in a pointer?

Answer 6

int *pointer = &var;
*pointer = 13;

Question 7

Given int pointer ‘pointer’, how do you assign the value in pointer’s memory to variable ‘var’?

Answer 7

int var = *pointer;

Question 8

How is pointer math performed assuming same pointer type?

Answer 8

The pointers will perform arithmatic in the units of the type.
ex: int *one - int *two = 1, assuming they were declared one after the other.

Question 9

Given array y, what does *y return?

Answer 9

The memory address of the first index.

Question 10

What is created with int *a;?

Answer 10

Movable pointer to writable int

Question 11

What is created with const int *b;?

Answer 11

Movable pointer to read-only int

Question 12

What is created with int *const c;?

Answer 12

unmoveable pointer writable int.

Question 13

What is created with const int *const d;?

Answer 13

unmovable pointer to read-only int.

Question 14

What is created with int &e = …;?

Answer 14

read/write reference int

Question 15

What is created with const int &f = …;?

Answer 15

read only reference

Question 16

How do you use allocated memory with a pointer?

Answer 16

With the ‘new’ keyword.

Question 17

What are the 2 keyword pairs to remember for heap memory allocation?

Answer 17

new/delete and new[]/delete[]

Question 18

What type of memory is on the heap?

Answer 18

Dynamic Memory

Question 19

How do you get access to the typeid function?

Answer 19

#include <typeinfo>

Question 20

What does typeid return?

Answer 20

A type_info object.

Question 21

What is useful about type_info objects?

Answer 21

They are comparable.

Question 22

What is the “this” keyword?

Answer 22

A pointer to an objects self.

Question 23

How do you interact with data inside a “this” pointer?

Answer 23

With the ‘->’ operator.

Question 24

Where should dynamic length array int[x] be allocated?

Answer 24

The heap.

Question 25

Where should fixed length array int[7] be allocated?

Answer 25

The stack.

Question 26

What does the ‘sizeof’ operator return?

Answer 26

The byte length of a variable / datatype.

Question 27

Given int array ‘arr’, how do you get the length of the array?

Answer 27

sizeof(arr) / sizeof(arr[0])

Question 28

Given ‘int arr[10];’, what does ‘sizeof(arr);’ return?

Answer 28

40

Question 29

What is the difference between new/delete and malloc/free?

Answer 29

new/delete will allocate / deallocate memory as well as the object to put in that memory, malloc/free only deal with the memory and not the object.

Question 30

How is memory cleared on the stack vs the heap?

Answer 30

Memory will only clear up on the stack when it falls out of scope, heap memory can be allocated, deallocated, and re-used at will.