C++ standard library 2

Question 1

blank are usually just sequences of bytes stored in your computer’s storage

Answer 1

files are usually just sequences of bytes stores in your computer’s storage

Question 2

two basic types of files:

Answer 2

text files

binary files

Question 3

are intended to be interpreted as a string of characters

can be produced and read with programs such as Notepad

Answer 3

text files 
.txt files
.cpp files
.py files
.html files

Question 4

are sequences of bytes intended to be interpreted according to a program-defined scheme

Answer 4

Binary files
.docx files
.jpg files
.mp3 files

Question 5

C++ allows us to work with text files using blank

Answer 5

streams

Question 6

to use text file must include

Two data types in #include blank

Answer 6

include fstream

Question 7

#include
input and output with file stream

Answer 7

ifstream: input file stream
ofstream: output file stream

Question 8

ifstream used for

ofstream used for

Answer 8

ifstream used for reading files

ofstream used for writing files

Question 9

to use file stream
blank them
and call blank with the name of the file you want to open:
example

Answer 9

declare them and call .open( )
ifstream fin;
fin.open(“filename.txt”);

ofstream fout; ;
fout.open(“filename.txt”);

Question 10

reading and writing files

to read data from an ifstream use blank and blank as you would with cin

Answer 10

use&raquo_space; and getline()

Question 11

example of ifstream reading data

Answer 11

fin&raquo_space; x&raquo_space; y;

Question 12

to write data to an ofstream, use blank as you would with cout

Answer 12

«

Question 13

example of writing data with ofstream

Answer 13

fout &laquo_space;x &laquo_space;” + “ &laquo_space;y &laquo_space;” is “ &laquo_space;x + y;

Question 14

when you are done, use blank to close the file

Answer 14

.close( )

Question 15

to ensure the file is properly closed and put away use blank

Answer 15

fin. close( );

fout. close( );

Question 16

C++ has a header called blank that contains various useful features for many programs

Answer 16

utility

Question 17

two utilities

Answer 17

pair data type
the swap ( ) function

Question 18

swapping variables
example
**old way

Answer 18

temp = x;
x = y;
y = temp;
**old way

Question 19

using a blank variable ensures that you don’t lose either value by overwriting it with the other
**old way

Answer 19

temporary value

**old way

Question 20

C++11 gave new way to swap using blank and blank

Answer 20

include utility and swap ( );

Question 21

the blank data type allow us to pair together two values of any types

Answer 21

pair data type

Question 22

declare a pair by specifying the types of the two items and using make_pair( );
example

Answer 22

pair p = make_pair(5, 2.5)

Question 23

to access the items in a pair, use blank and blank

Answer 23

.first and .second

Question 24

to access the items in a pair, use .first and .second

Answer 24

cout &laquo_space;p.first &laquo_space;”, “ &laquo_space;p.second &laquo_space;“\n” ;

Question 25

maps can be traversed with blank

Answer 25

range-for loops

Question 26

the value of the loop control variable at each step is a pair of the blank and blank

Answer 26

the value of the loop control variable at each step is a pair of the key and mapped value types

Question 27

example of loop control variable m

pairs and maps

Answer 27

map scores; 
// add some values to scores...

for(pair kv: scores)
{
cout &laquo_space;kv.first <

Question 28

Many of the things C++ can do with containers such as vector or map involve using the containers’ blank

Answer 28

iterators

Question 29

blank is a way of referring to an item in a container without needing an index

Answer 29

iterator

Question 30

each blank has its own iterator type

Answer 30

each container has its own iterator type

Question 31

Container types, like vector, have two key methods for using iterators

Answer 31

.begin( )

.end( )

Question 32

returns an iterator referring to the first item in the container

Answer 32

.begin( )

Question 33

returns an iterator indicating that the end has been reached

Answer 33

.end( )

Question 34

the most basic way to use iterators is in a blank as a replacement for the index

Answer 34

for loop as a replacement for the index

Question 35

vector numbers = { 1, 2, 3 };
for (vector : : iterator it = numbers.begin( ); 
{
  cout << *it << "\n";
}

Answer 35

vector : : iterator is the type for the iterator for a vector of ints
iterators types are attached to the container type

Question 36

iterator types are attached to the container type with blank

Answer 36

: :

Question 37

it++ moves the iterator to the blank

Answer 37

next item

Question 38

*it access the item itself though the iterator; * is the dereference operator

Answer 38

True

Question 39

Adding to or subtracting from an iterator yields the iterator for a different item in the sequence
example: it + 5 moves the iterator blank
it - 2 moves the iterator blank

Answer 39

it + 5 moves the operator forward five items

it -2 moves the iterator two items backward

Question 40

this is why it++ moves the iterator blank

Answer 40

forward: it adds one to it

Question 41

blank can also be used to assign values to the items they represent

Answer 41

iterators

Question 42

example of iterators

code adds one to every value in the vector

Answer 42

for(vector::iterator it = numbers.begin( ); it!= numbers.end(); it++)
{
*it = *it + 1;
}

Question 43

.cbegin( ) and .cend( ) means

Answer 43

constant iterators

not modifiable

Question 44

blank are useful when working with maps, as they follow assignment

Answer 44

iterators

Question 45

examples of map iterators

Answer 45

map scores;
scores[“Alice”] = 99.5
scores[“Blake”] = 115
scores[“Natalie”] = 103

for (map:: iterator it = scores.begin( ); it != scores.end( ); it++)
{
(it).second = (it).second + 1.5;
}

Question 46

dereferencing the map iterator gives you a blank, hence the use of .second

Answer 46

pair object

Question 47

blank omits the full iterator type by using this keyword

Answer 47

auto

Question 48

example of using auto

Answer 48

for(auto it = numbers.begin(); it != numbers. end(); it++)
{
*it = *it + 1;
}

Question 49

blank word backwards through the collection

Answer 49

reverse iterators

Question 50

examples of reverse operators

Answer 50

.rbegin( ) and .rend( )

Question 51

the blank header has functions for performing various operations with containers

Answer 51

algorithm

Question 52

the blank function can replace one value with another

Answer 52

replace( )
example replace(numbers.begin( ), numbers.end( ), 5, 15);

Question 53

the blank function returns true if the values are in ascending order, and false if not

Answer 53

is_sorted( ) function
example: if (is_sorted(numbers.begin( ), numbers.end( )))
{
cout &laquo_space;“these are in ascending order”;
}

Question 54

the blank function will put the items in ascending order

Answer 54

sort( ) function