pointers, dynamic memory allocation, objects with dynamically allocated members, and vectors

Question 1

vector

Answer 1

Stores elements like an array but can dynamically change in size. Adding and removing of elements are usually done at the end. Elements can be accessed by index.

Question 2

stack

Answer 2

Stores elements in a specific order, called LIFO (Last In, First Out), where elements can only be added and removed from the top. Not accessible by index.

Question 3

queue

Answer 3

Stores elements in a specific order, called FIFO (First In, First Out), where elements are added at the end and removed from the front. Not accessible by index.

Question 4

what do you need to use vectors?

Answer 4

include<vector></vector>

Question 5

how do you declare a vector?

Answer 5

vector<type> vectorName;</type>

Question 6

how do you declare a vector with 5 positions?

Answer 6

vector<type> vectorName (5);</type>

Question 7

how do you declare vector Cars of type string with entries Volvo, BMW, and Dodge?

Answer 7

vector<string> Cars = {Volvo, BMW, Dodge};</string>

Question 8

how do you write a for each loop?

Answer 8

for ( type of variable in vector variable name : vector name)

Question 9

how do you print out vector entries using a for each loop?

Answer 9

for( type of variable in vector variable name: vector name) { cout &laquo_space;variable name; }

Question 10

iterators

Answer 10

used to access and iterate through elements of data structures (vectors, sets, etc.), by “pointing” to them

Question 11

algorithms

Answer 11

include functions, like sort() and find(), that perform operations on data structures through iterators

Question 12

can the type of vector (string, int, double, …) be changed after a vector has been declared?

Answer 12

no

Question 13

how can you access vector elements using brackets?

Answer 13

vectorName[positionOfElement];

Question 14

what does .front() do?

Answer 14

accesses the first element in the vector

Question 15

what does .back() do?

Answer 15

accesses the last element in the vector

Question 16

what does .push_back() do?

Answer 16

adds an element at the end of the vector

Question 17

what does pop.back() do?

Answer 17

removes the last element from the vector

Question 18

what function returns how many elements a vector has?

Answer 18

.size()

Question 19

how do you check if a vector is empty?

Answer 19

using the .empty() function included in the vector library

Question 20

what does .empty() return?

Answer 20

1 (true) if the vector is empty
0 (false) if the vector is not empty

Question 21

begin()

Answer 21

returns an iterator that points to the first element of the data structure

Question 22

end()

Answer 22

returns an iterator that points to one position after the last element

Question 23

when should you use an iterator over a for loop?

Answer 23

when you need to add, modify, or remove elements during iteration, iterate in reverse, or skip elements

Question 24

what do you need to be able to use sort() and find()?

Answer 24

include<algorithm></algorithm>

Question 25

how do you use sort() to sort the entire vector?

Answer 25

sort(vectorName.begin(), vectorName.end());

Question 26

how do you use find() to search an entire vector for the number 55?

Answer 26

find(vectorName.begin(), vectorName.end(), 55);

Question 27

what does find() return?

Answer 27

an iterator pointing to the element

Question 28

what are the two ways memory can be allocated?

Answer 28

at compile time or at run time

Question 29

heap

Answer 29

It is the unused memory of the program and can be used to allocate the memory at runtime dynamically

Question 30

what is the reference operator?

Answer 30

&

Question 31

what is the dereference operator?

Answer 31

*

Question 32

keyword for allocating memory

Answer 32

new

Question 33

keyword for deallocating memory

Answer 33

delete

Question 34

static variable / constant

Answer 34

memory location known at compile time

Question 35

automatic variable

Answer 35

if we don't invoke the function the variable is located in, the memory will not be allocated

Question 36

memory leak problem

Answer 36

when you reassign a pointer that already has a memory address (the program will get confused and not know which one to output)

Question 37

int* ptr = new int; delete ptr; *ptr = 5; what is the issue with this code?

Answer 37

loose pointer problem, because we just deleted the memory address of ptr and then tried to assign a numerical value to a nonexistent memory location

Question 38

int* p1; p1 = new int [10]; what is happening in the code above?

Answer 38

a pointer p1 is created, then it reserves 10 consecutive memory addresses (dynamically allocated array with 10 positions)

Question 39

assume class myClass has two int and one int pointer variables. myClass obj = {1, 10, 2}; delete obj; what, if anything, is wrong with this code?

Answer 39

you should not use delete with a class object because it will not deallocate the dynamic memory in the class. In this example, it will not properly deallocate the int pointer variable.

Question 40

how do you declare a copy constructor?

Answer 40

className(const className objectName&)

Question 41

how should you copy objects with pointers?

Answer 41

by overloading the = operator

Question 42

can you pass a vector with or without &?

Answer 42

yes

Question 43

how do you declare an iterator?

Answer 43

vector::iterator iteratorName = .... (usually the first element of the vector)

Question 44

how do you insert an element into a vector using an iterator?

Answer 44

vectorName.insert(iteratorName, thing to insert) --> (inserts the thing at the iterator's position)

Question 45

how do you erase an element in a vector using an iterator?

Answer 45

vectorName.erase(iteratorName); --> erases the element at the iterators position

Question 46

what do you need to be able to use iterators?

Answer 46

#include iterator

Question 47

how do you overload the + operator?

Answer 47

className operator+ (const className variableName&)