C++ Chapter 2 Storing Data In C++

Front 1

modulus

Back 1

-C++ language for the remainder

Front 2

#include <iostream>
using namespace std;
int main()
{
int start;
int time;
start = 37;
time = 22;
cout << start + time << endl;
return 0;
}

Back 2

identifies i/o stream and uses the namespace of standard library

-declares two variables
-assigns values

(intializes variables in two steps)

displays the total of 37 and 22 by adding their variables and sending them to the console

Front 3

#include <iostream>
using namespace std;
int main()
{
int start;
int time;
int total;
start = 37;
time = 22;
total = start + time;
cout << total << endl;
return 0;
}

Back 3

prints the variable total which is set to the sum of start and time

Front 4

total = start + 5;
cout << total << endl;

What can you assume of the variable total...

Back 4

total is an int

total is the sum of the integer contained in the variable start and the 5

Front 5

total = total + 5;

Back 5

This statement really just means we’re going to add 5 to the value stored in
total, and we’ll take the value we get back and store it back in total. In
other words, total will now be 5 greater than it was to begin with.
The following code shows this in action:
#include <iostream>
using namespace std;
int main()
{
int total;
total = 12;
cout << total << endl;
total = total + 5;
cout << total << endl;
return

Front 6

Computer Variables vs Math Variables

Back 6

Computer variables serve as abstract representations for other values HOWEVER unless specified variables are not constant and in actuality serve more as containers that hold value vs naming devices that represent a specific value

Front 7

total = total + 5; re write in short hand

Back 7

total +=5

Front 8

total += time; re write in longhand

Back 8

total = total + time

Front 9

total = total + 1

Back 9

total++

Front 10

total++

Back 10

adds the value of one to the variable

Front 11

Add two variables

Back 11

example

cout << start + time
<< endl;

Front 12

Add a variable and a number

Back 12

example

cout << start + 5 << endl;

Front 13

Add two variables and save the result in a
variable

Back 13

example

total = start + finish

Front 14

Add a variable and a number and save the
result in a variable

Back 14

example

total = start + 8

Front 15

Add a number to what’s already in a variable

Back 15

example

total = total + 2

||

total +=2

Front 16

Add a number to what’s already in a variable
by using a shortcut

Back 16

example

total +=2

Front 17

Add a variable to what’s already in a variable

Back 17

total = total + time

Front 18

Add a variable to what’s already in a
variable by using a shortcut

Back 18

totale += time

Front 19

Add 1 to a variable

Back 19

total++

Front 20

why C++?

Back 20

- adding one thing to the C language OBJECT_ORIENTED-PROGRAMMING!!!!

Front 21

final = final - time

Shorthand and what is happening

Back 21

final -= time

final is being reassigned the a value of its starting value minus the value contained in the variable time

Front 22

final = final - 1

Back 22

final--

Front 23

total = total * multiplier;

shorthand and explain

Back 23

total *= multiplier;

the new total is equal to the previous value of total times multiplier

Front 24

C++ and division

Back 24

So in terms of strictly whole numbers, the answer to 21 divided by 5 is 4
remainder 1. And that’s how the computer does arithmetic with integers: It
gets two different answers: The quotient and the remainder. In math terms,
the main answer (in our example, 4) is called the quotient. And what’s left
over is the remainder.

Front 25

the two components to the a division problem in C++

Back 25

quotient and remainder

Front 26

to find quotient use what operator

Back 26

(/) foward slash division operator

Front 27

to find the remainder use

Back 27

To find the remainder, use the percent sign (%). This is often called the
modulus operator.

used to find remainder using ints not neccesary for floating point variables

Front 28

int / float = what will the answer be?

Back 28

the answer will be a float

Front 29

int first = 10 ;
first = first / 5;

shorthand and explain

Back 29

first /= 5;

the the integer value held in the variable first is divided by 5 and reassigned with the quotient value

Front 30

int first = 33;
first %= 5;
cout << first << endl;

Back 30

the variable first is reassigned the remainder value of 33 % 5

Front 31

char variables

Back 31

- hold just ONE character

- use single quotes to identify character

Front 32

Null character

Back 32

- \0

-But the null
character is important because it is often used to signify the end of something

-nonprintable character

Front 33

NAMES OF SYMBOLS

Back 33

. dot (but not period or decimal point)

@ at

& ampersand (but not and)

# pound (but not number sign)

! bang, but most people still say exclamation point

~ tilde

% percent

* star (not asterisk)

( left paren or left parenthesis

) right paren or right parenthesis

[ left square bracket or left bracket

] right square bracket or right bracket

== equal-equal (not double equal)

++ plus-plus (not double plus)

– – minus-minus (not double minus)

/ forward slash

\ backslash

{ left brace or left curly brace or open brace

} right brace or right curly brace or close brace

^ caret, but a few people say hat (for real — no joke here!)

“ double quote

Front 34

char ch = ' " '

Back 34

A way o placing quotes without having to use the convention of \"

Front 35

Backslashes

Back 35

When the compiler sees a backslash inside a string or a character, it treats
the backslash as special and looks at whatever follows it. If you have something
like ‘\’ with no other character inside the single quotes following it,
the compiler thinks the final quote is to be combined with the backslash.
And then it moves forward, expecting a single quote to follow, representing
the end. Because a single quote doesn’t appear, the compiler gets confused
and issues an error.

Front 36

string (a simplified definition)

Back 36

short, a string is simply a set of characters strung
together. The compiler knows the start and end of a string in your code
based on the location of the double quotes

Front 37

mystring = “Hello there”;

use encapsulation

Back 37

mystring(“Hello there”);

Front 38

Using Brackets to Access Individual Characters in a String

Back 38

mystring[3] is equal to the fourth character in mystring

Front 39

#include <string>

Back 39

This line means that your program is making
use of another file somewhere, and that file has
a filename of string. Inside that other file
is a bunch of C++ code that essentially gives
your program the ability to understand strings.

Front 40

#include <iostream>

Back 40

gives your program the ability to write to the
console, among other things.

Front 41

mystring[3]

what does the 3 represent and what is it called?

Back 41

-fourth position in mystring

- (The number inside brackets is
called an index.)

Front 42

string mystring;
mystring = “abcdef”;
char mychar = mystring[2];
cout << mychar << endl;

what character is contained by mychar?

Back 42

'c'

Front 43

string x = “abcdef”;
x[1] = ‘q’;
cout << x << endl;

Back 43

index 1 is equal to 'q' changing string x to "aqcdef"

Front 44

string mystring;
mystring = “Hi “;
mystring += “there”;
cout << mystring << endl;

Back 44

console "Hi there"

The first line declares the string mystring. The second line initializes it to
“Hi ”. But what does the third line do? The third line uses the += operator,
which appends something to the string, in this case “there”. Thus, after
this line runs, the string called mystring contains the string “Hi there”,
and that’s what appears on the console when the cout line runs. The fancy
programmer term for adding something to a string is concatenation.

Front 45

concatenation

Back 45

adding something to a string

Front 46

string first = “hello “;
string second = “there”;
string third = first + second;
cout << third << endl;

Back 46

This code prints the value of third, which is simply the two strings pushed
together, in other words, “hello there”. (Notice the string called first
has a space at its end, which is inside quotes and, therefore, part of the
string.)

Front 47

string constant

Back 47

an actual string in your program
surrounded by quotes

Front 48

add a string constant

Back 48

mystring += "string constant";

mystring = yourString + "string constant";

Front 49

how do you index into a string

Back 49

[position number] by placing the position number you wish to access between square brackets

Front 50

result = (first == second) ? “equal” : “not equal”;

what does it mean?
what does result equal?

Back 50

if int first is equal to int second than string result contains "equal" otherwise "not equal"

book:
And once again, consider what it means: If first is equal to second,
result gets “equal”; otherwise, it gets “not equal”.

Front 51

Using the Conditional Operator to Do Comparisons example

Back 51

#include <iostream>
using namespace std;
int main()
{
int first = 10;
int second = 20;
string result;
result = first == second ? “equal” : “not equal”;
cout << result << endl;
return 0;
}

Front 52

result = (first == second) ?
“equal” : “not equal”;

using Boolean

Back 52

bool isequal;

isequal = (first == second);
result = isequal ? “equal” :
“not equal”;

Front 53

bool isequal;

isequal = (first == second);
result = isequal ? “equal” :
“not equal”;

explain.

Back 53

1) isqual declared as a boolean variable

bool isequal;

2) The second line sets this
to the value first == second. In other words, if first is equal to second, then
isequal gets the value true. Otherwise, isequal gets the value false.

isequal = (first == second);

3) In the third
line, result gets the value “equal” if
isequal is true; or result gets the value
“not equal” if isequal is false.

result = isequal ? “equal” :
“not equal”;

Front 54

Boolean expression

Back 54

that the code requires a Boolean
value. Therefore, you can throw in a Boolean
variable if you prefer, because a Boolean variable
holds a Boolean value.

Front 55

bool finished;

Back 55

This declares a Boolean variable called finished. Then, you can either put
a true or a false in this variable, as in the following:
finished = true;
or
finished = false;
When you print the value of a Boolean variable by using code like the
following
cout << finished << endl;
you see either a 1 for true or a 0 for false. The reason is that, deep down
inside, the computer stores a 1 to represent true and a 0 to represent
false.

Front 56

1

Back 56

true

Front 57

0

Back 57

false

Front 58

cin

Back 58

- reading from the console

- uses extraction operator (>>) extractinginto the stream

Front 59

cout uses what operator

Back 59

-- insertion operator (<<)

Front 60

#include <iostream>
using namespace std;
int main()
{
string name;
cout << “Type your name: “;
cin >> name;
cout << “Your name is “ << name << endl;
return 0;
}

Back 60

1) string name is declared
2) user input is stored in string name
3) string name is displayed

Front 61

#include <iostream>
using namespace std;
int main()
{
string name;
cout << “Type your name: “;
cin >> name;
cout << “Your name is “ << name << endl;
return 0;
}

Back 61

Type your name: Fred
Your name is Fred