Discussion 1: C++ Refresher

Question 1

preprocessor directives

Answer 1

top of file with a #, processed before the compiler, #include, #define, (#ifdef, #ifndef, #endif), #pragma once

Question 2

include

Answer 2

include replaces the directive with the content of the specified header or file

Question 3

define (

Answer 3

define replaces all instances of identifier with replacement.

Question 4

ifdef, ifndef, and #endif

Answer 4

identifiers allows sections to be complied if an identifier is/isnt defined

Question 5

pragma once

Answer 5

makes source file to be included only once in a single compilation

Question 6

char

Answer 6

1 byte | primitive type

Question 7

std::string( char array )

Answer 7

char array

Question 8

int (How many bytes, range)

Answer 8

4 bytes | -2.147 bil - 2.147 bil

Question 9

unsigned int (How many bytes, range)

Answer 9

4 bytes | 0 to 4.294 bil

Question 10

long (how many bytes, range)

Answer 10

8 bytes | -910^18 to 910^18

Question 11

unsigned long (bytes, range)

Answer 11

8 bytes | 0 to 18*10^18

Question 12

double (bytes, use case)

Answer 12

8 bytes | used for decimals

Question 13

float (bytes, use case)

Answer 13

4 bytes | used for decimals

Question 14

float vs double

Answer 14

float uses 4 bytes , double uses 8 bytes.
Use case: double is more precise

Question 15

bool

Answer 15

1 byte | True or False

Question 16

void

Answer 16

0 bytes | function not returning anything

Question 17

std::string( char array ) vs std::string

Answer 17

std::string(char array) is an array of characters while string is not

Question 18

auto (keyword)

Answer 18

derives the type of a variable on the fly

Question 19

decltype (keyword)

Answer 19

derives the type of variable by using another variable

Question 20

pointers

Answer 20

variable whose value is the memory address of another variable

Question 21

pointer (syntax)

Answer 21

*

Question 22

Address-of Operator

Answer 22

& | gets the memory address of a variable

Question 23

Dereference Operator

Answer 23

• | gets the value at the memory address of a pointer

Question 24

pointer of array

Answer 24

points at the first element of the array

Question 25

array vs vector

Answer 25

array is just a pointer to its first elements. It has no knowledge of where it ends

Question 26

new (keyword)

Answer 26

dynamically allocates memory in the heap, and returns a pointer

Question 27

delete (keyword)

Answer 27

used to deallocate heap memory. delete or delete[] , pointer is not destroyed but the item the pointing is referencing is.

Question 28

memory leak

Answer 28

dynamic memory (heap) that is no longer being referenced and not deleted

Question 29

passing into functions in c++

Answer 29

pass by pointer, or reference, if not it will create a copy of passed in argument

Question 30

structs vs class

Answer 30

both create object, structs are public by default, while class is private by default

Question 31

templates

Answer 31

used when we don’t know the type it will receive. usually used at very low level

Question 32

T o F: (Templates) We can write one template function that can be used for all data types including user defined types. Like sort(), max(), min(), etc

Answer 32

TRUE

Question 33

T o F: (Templates) We can write one template class or struct that can be used for all data types including user defined types. Like LinkedList, Stack, Queue, etc…

Answer 33

TRUE

Question 34

T o F: (Templates) Templates are an example of overriding

Answer 34

FALSE

Question 35

const

Answer 35

variable is NOT allowed to change

Question 36

What is mutable? int* const x

Answer 36

the memory address is locked, but the int value can change

Question 37

What is mutable? const int* x or int const * x

Answer 37

The int cannot change, but the memory address can be changed.

Question 38

What is mutable? const int * const x

Answer 38

The int and memory address cannot be changed.

Question 39

const objects, can only be called by

Answer 39

const functions