![Page 1: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/1.jpg)
Introduction to C++
![Page 2: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/2.jpg)
2.12.1The Parts of a C++ Program
–Anatomy of a simple C++ program
![Page 3: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/3.jpg)
The Parts of a C++ The Parts of a C++ ProgramProgram
// sample C++ program
#include <iostream>
using namespace std;
int main()
{
cout << "Hello, there!";
return 0;
}
preprocessor directive
comment
which namespace to use
beginning of function named main
beginning of block for mainoutput statement
end of block for main
string literalsend 0 to operating system
Hello, there!
![Page 4: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/4.jpg)
A different exampleA different example
// sample C++ program
#include <iostream>
using namespace std;
int main ()
{
int a, b = 1;
a = b + b++;
printf ("%d\n", a);
return 0;
}
preprocessor directive
comment
which namespace to use
beginning of function named main
beginning of block for main
output statement
end of block for main
send 0 to operating system
variable declaration
Increment and Addition operations
2
![Page 5: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/5.jpg)
Special CharactersSpecial CharactersCharacter Name Meaning
// Double slash Beginning of a comment
# Pound sign Beginning of preprocessor directive
< > Open/close brackets Enclose filename in #include
( ) Open/close parentheses
Used when naming a function
{ } Open/close brace Encloses a group of statements
" " Open/close quotation marks
Encloses string of characters
; Semicolon End of a programming statement
/* */ Slash * Comment
![Page 6: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/6.jpg)
2.22.2The cout Object
![Page 7: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/7.jpg)
The The coutcout Object ObjectDisplays output on the computer
screen
You use the stream insertion operator << to send output to cout:
cout << "Programming is fun!";Programming is fun!
![Page 8: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/8.jpg)
The The coutcout Object ObjectCan be used to send more than
one item to cout:
cout << "Hello " << "there!";Or:
cout << "Hello ";cout << "there!";
Hello there!
![Page 9: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/9.jpg)
The The coutcout Object ObjectThis produces one line of output:
cout << "Programming is ";cout << "fun!";
Programming is fun!
![Page 10: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/10.jpg)
The The endlendl Manipulator ManipulatorYou can use the endl manipulator to
start a new line of output. This will produce two lines of output:
cout << "Programming is" << endl;cout << "fun!";
Programming isfun!
![Page 11: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/11.jpg)
The The endlendl Manipulator Manipulator
cout << "Programming is" << endl;cout << "fun!";
Programming isfun!
![Page 12: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/12.jpg)
The The endlendl Manipulator ManipulatorYou do NOT put quotation marks
around endl
The last character in endl is a lowercase L, not the number 1.
endl This is a lowercase L
![Page 13: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/13.jpg)
The The \n \n Escape SequenceEscape SequenceYou can also use the \n escape
sequence to start a new line of output. This will produce two lines of output:
cout << "Programming is\n";cout << "fun!";
Notice that the \n is INSIDE
the string.
![Page 14: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/14.jpg)
The The \n \n Escape SequenceEscape Sequence
cout << "Programming is\n";cout << "fun!";
Programming isfun!
![Page 15: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/15.jpg)
Escape Sequence for use Escape Sequence for use with output (cout)with output (cout)
Escape Sequence
Name Meaning
\n Newline Cursor to go to next line for printing
\t Horizontal tab Cursor to go to next tab stop
\a Alarm Computer to beep
\b Backspace Cursor to back up or left one position
\r Return Cursor to start of current line
\\ Backslash Print backsplash
\’ Single quote Print quotation mark
\” Double quote Print double quotation
![Page 16: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/16.jpg)
cout with variablescout with variables
int number;
number = 10;
cout << “The number is “ << number << endl;
The number is 10
Only pass variable name, no quotes around it
![Page 17: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/17.jpg)
2.32.3The #include Directive
![Page 18: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/18.jpg)
The The #include#include Directive DirectiveInserts the contents of another file
into the programThis is a preprocessor directive, not
part of C++ language#include lines not seen by compiler#include lines ARE seen by
preprocessorDo not place a semicolon at end of #include line (this is syntax you just have to remember)
![Page 19: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/19.jpg)
Recall the Preprocessor ….Recall the Preprocessor ….a) Create file containing the program
with a text editor.b) Run preprocessor to convert source
file directives to source code program statements.
c) Run compiler to convert source program into machine instructions.
d) Run linker to connect hardware-specific code to machine instructions, producing an executable file.
Steps b–d are often performed by a single command or button click.
Errors detected at any step will prevent execution of following steps.
Compiled Languages
![Page 20: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/20.jpg)
Example #includeExample #includeHere we include iostream which has
the cout object in it This is the input-output stream library. iostream is a header file
// sample C++ program
#include <iostream>
using namespace std;
int main()
{
cout << "Hello, there!";
return 0;
}
preprocessor directive
The preprocessor will insert ATthis point in the code the entire contents of iostream header file atthis point of the program. Its contents include the definition of cout object
Where is this file iostream???---answer the <> around it tells the preprocessor it is in a standard location. This is typically downloaded and installed for you when you install C++ (typically there will be an /include directory somewhere in install)
![Page 21: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/21.jpg)
#include <filename> versus #include <filename> versus #include “/path/filename.h”#include “/path/filename.h”#include <filename>
◦ Looks in the IDE C++ devloper tools standard include directories that were created at install time for the file.
#include “/path/filename.h”◦ Looks for the filename.h file in the /path/ directory
path.◦ Used when you are creating your own files (we will
learn later how to do) OR when you have downloaded some 3rd party non-standard C++ header files.
We will see more about thislater in the course
![Page 22: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/22.jpg)
2.42.4Variables and Literals
![Page 23: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/23.jpg)
Variables and LiteralsVariables and LiteralsVariable: a storage location in
memory
◦Has a name and a type of data it can hold
◦Must be defined before it can be used:
int item;
int = type and stands for integeritem = variable name
![Page 24: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/24.jpg)
Variable Definition in Variable Definition in Program 2-7Program 2-7
Variable Definition
![Page 25: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/25.jpg)
Variables can change Variables can change valuevalue
int item; item = 2; item = 99;
CHANGING the value of item from2 to 99
![Page 26: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/26.jpg)
What can variables be What can variables be used for?used for?Store Information a User might type inStore information from a fileStore information from a database your program
needs to operateStore information representing system information
(i.e. ask the date, time, o.s. info, call system functions and get results)
Store information from calculations (from data above or generated—i.e. a timer)
Store information given to it from another programStore information from other machines/services
across network/internet/webMore….
![Page 27: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/27.jpg)
LiteralsLiteralsLiteral: a value that is written
into a program’s code.
"hello, there" (string literal)12 (integer literal)
99.33 (floating point literal)
![Page 28: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/28.jpg)
Integer Literal in Program Integer Literal in Program 2-92-9
20 is an integer literal
![Page 29: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/29.jpg)
String Literals in Program String Literals in Program 2-92-9
These are string literals
![Page 30: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/30.jpg)
QuestionQuestionWhat kind of literal is “5” ?
Answer = a string (NOT a number)
![Page 31: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/31.jpg)
2.52.5Identifiers
![Page 32: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/32.jpg)
IdentifiersIdentifiersAn identifier is a programmer-
defined name for some part of a program: variables, functions, etc.
![Page 33: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/33.jpg)
C++ Key WordsC++ Key Words
You cannot use any of the C++ key words as an identifier. These words have reserved meaning.
This means (in general) you should not use these as variable names
![Page 34: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/34.jpg)
Variable NamesVariable NamesA variable name should represent the
purpose of the variable. For example:
itemsOrdered
The purpose of this variable is to hold the number of items ordered.
But it could also have the meaning of holding a list of the items that were ordered. Is there a better variable name? How about numItemsOrdered?
Notice the conventionstart with lower case letter and then as chaintogether words for meaning start of each wordis capitalizede.g. dogListor currentTime
![Page 35: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/35.jpg)
Identifier RulesIdentifier RulesThe first character of an identifier
must be an alphabetic character or and underscore ( _ ),
After the first character you may use ONLY alphabetic characters, numbers, or underscore characters.
Upper- and lowercase characters are distinct (this means U is different than u) This is called case sensitive.
![Page 36: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/36.jpg)
Valid and Invalid Valid and Invalid IdentifiersIdentifiers
IDENTIFIER VALID? REASON IF INVALID
totalSales Yes
total_Sales Yes
total.Sales No Cannot contain .
4thQtrSales No Cannot begin with digit
totalSale$ No Cannot contain $
![Page 37: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/37.jpg)
2.62.6Integer Data Types
![Page 38: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/38.jpg)
Integer Data TypesInteger Data Types
• Integer variables can hold whole numbers such as 12, 7, and -99.
![Page 39: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/39.jpg)
Wait a minute???Wait a minute???int and long look the same?
◦4 bytes with same range
Well, this can be implementation dependent. ◦i.e. on 32 bit window machines it long is 4
bytes but, on some Unix machines it can be 8 bytes.
So –what we really know is sizeof(long) >= sizeof(int) >= 4 bytes
Why did this happen?Original int was intended tobe the “natural” word size ofa processor…but, nowmany modern processors have changed and can holddifferent word sizes
![Page 40: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/40.jpg)
Defining VariablesDefining VariablesVariables of the same type can be defined
- On separate lines:int length;int width;unsigned int area;
- On the same line:int length, width;unsigned int area;
Variables of different types must be in different definitions
![Page 41: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/41.jpg)
Integer Types in Program Integer Types in Program 2-102-10
This program has three variables: checking, miles, and days
![Page 42: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/42.jpg)
Integer LiteralsInteger LiteralsAn integer literal is an integer
value that is typed into a program’s code. For example:
itemsOrdered = 15;
In this code, 15 is an integer literal.
![Page 43: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/43.jpg)
Integer Literals in Program Integer Literals in Program 2-102-10
Integer Literals
Here we are initializing the variables to literal values
![Page 44: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/44.jpg)
Integer LiteralsInteger LiteralsInteger literals are stored in
memory as ints by defaultTo store an integer constant in a
long memory location, put ‘L’ at the end of the number: 1234L
Constants that begin with ‘0’ (zero) are base 8: 075
Constants that begin with ‘0x’ are base 16: 0x75A
![Page 45: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/45.jpg)
2.72.7The char Data Type
![Page 46: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/46.jpg)
The The charchar Data Type Data TypeUsed to hold characters or very
small integer values i.e. greyscale images have each pixel
represented by 8 bits of information
Usually 1 byte of memoryNumeric value of character from
the character set is stored in memory:CODE:
char letter;letter = 'C';
MEMORY:letter
67
![Page 47: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/47.jpg)
Character LiteralsCharacter LiteralsCharacter literals must be
enclosed in single quote marks. Example:
'A'
![Page 48: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/48.jpg)
Character Literals in Program Character Literals in Program 2-132-13
![Page 49: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/49.jpg)
Character StringsCharacter StringsA series of characters in consecutive
memory locations:"Hello"
Stored with the null terminator, \0, at the end:
Comprised of the characters between the " "
H e l l o \0
![Page 50: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/50.jpg)
2.82.8The C++ string Class
![Page 51: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/51.jpg)
The C++ The C++ stringstring Class ClassSpecial data type supports working
with strings #include <string>Can define string variables in
programs:string firstName, lastName;
Can receive values with assignment operator:firstName = "George";lastName = "Washington";
Can be displayed via coutcout << firstName << " " << lastName;
Remember this means thereis a string header file in a standard/include directory that was installed
![Page 52: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/52.jpg)
The The stringstring class in Program class in Program 2-152-15
![Page 53: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/53.jpg)
2.92.9Floating-Point Data Types
![Page 54: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/54.jpg)
Floating-Point Data TypesFloating-Point Data TypesThe floating-point data types are:floatdoublelong double
They can hold real numbers such as:12.45 -3.8
Stored in a form similar to scientific notation
All floating-point numbers are signed
![Page 55: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/55.jpg)
Floating-Point Data TypesFloating-Point Data Types
Remember our discussion about the size of long and int ---- this applies here for double and long double
![Page 56: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/56.jpg)
Floating-Point LiteralsFloating-Point LiteralsCan be represented in
◦Fixed point (decimal) notation:31.4159 0.0000625
◦E notation:3.14159E1 6.25e-5
Are double by defaultCan be forced to be float
(3.14159f) or long double (0.0000625L)
![Page 57: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/57.jpg)
Floating-Point Data Types in Floating-Point Data Types in Program 2-16Program 2-16
![Page 58: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/58.jpg)
2.102.10The bool Data Type
![Page 59: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/59.jpg)
The The boolbool Data Type Data TypeRepresents values that are true
or false
bool variables are stored as small integers
false is represented by 0, true by 1:
bool allDone = true;
bool finished = false;
allDone finished
1 0
true andfalse are C++keywords
![Page 60: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/60.jpg)
Boolean Variables in Program Boolean Variables in Program 2-172-17
![Page 61: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/61.jpg)
2.112.11Determining the Size of a Data Type
![Page 62: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/62.jpg)
Determining the Size of a Determining the Size of a Data TypeData Type
The sizeof operator gives the size of any data type or variable:double amount;
cout << "A double is stored in "
<< sizeof(double) << "bytes\n";
cout << "Variable amount is stored in "
<< sizeof(amount)
<< "bytes\n";sizeof is afunction in C++
![Page 63: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/63.jpg)
2.122.12Variable Assignments and Initialization
![Page 64: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/64.jpg)
Variable Assignments and Variable Assignments and InitializationInitializationAn assignment statement uses
the = operator to store a value in a variable.
item = 12;
This statement assigns the value 12 to the item variable.
![Page 65: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/65.jpg)
AssignmentAssignmentThe variable receiving the value
must appear on the left side of the = operator.
This will NOT work:
// ERROR! 12 = item;
![Page 66: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/66.jpg)
Variable InitializationVariable InitializationTo initialize a variable means to
assign it a value when it is defined:
int length = 12;
Can initialize some or all variables:int length = 12, width = 5, area;
![Page 67: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/67.jpg)
Variable Initialization in Variable Initialization in Program 2-19Program 2-19
![Page 68: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/68.jpg)
Declaring Variables With the Declaring Variables With the autoauto Key Key WordWord
C++ 11 introduces an alternative way to define variables, using the auto key word and an initialization value. Here is an example:
auto amount = 100;The auto key word tells the compiler to
determine the variable’s data type from the initialization value.
auto interestRate= 12.0;
auto stockCode = 'D';
auto customerNum = 459L;
int
double
char
long
![Page 69: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/69.jpg)
2.132.13Scope
![Page 70: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/70.jpg)
ScopeScopeThe scope of a variable: the part
of the program in which the variable can be accessed
A variable cannot be used before it is defined
![Page 71: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/71.jpg)
Variable Out of Scope in Variable Out of Scope in Program 2-20Program 2-20
Can’t use a variablebefore it is declared
![Page 72: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/72.jpg)
2.142.14Arithmetic Operators
![Page 73: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/73.jpg)
Arithmetic OperatorsArithmetic OperatorsUsed for performing numeric
calculationsC++ has unary, binary, and
ternary operators:◦unary (1 operand) -5
◦binary (2 operands) 13 - 7
◦ternary (3 operands) exp1 ? exp2 : exp3
operand = arguments or items that the operating is operating on.-5 here the operand is 513 – 7 here the operands are 13 and 7Exp1 ? Exp2 : exp3 here the operands are exp1,exp2 and exp3
![Page 74: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/74.jpg)
Binary Arithmetic Binary Arithmetic OperatorsOperators
SYMBOL OPERATION EXAMPLE VALUE OF ans
+ addition ans = 7 + 3; 10
- subtraction ans = 7 - 3; 4
* multiplication ans = 7 * 3; 21
/ division ans = 7 / 3; 2
% modulus ans = 7 % 3; 1
remember binary here means 2 operands
![Page 75: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/75.jpg)
Arithmetic Operators in Arithmetic Operators in Program 2-21Program 2-21 here we are using the *, multiplication operator
and +, the addition operator
![Page 76: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/76.jpg)
A Closer Look at the A Closer Look at the // OperatorOperator
/ (division) operator performs integer division if both operands are integerscout << 13 / 5; // displays 2cout << 91 / 7; // displays 13
If either operand is floating point, the result is floating pointcout << 13 / 5.0; // displays 2.6cout << 91.0 / 7; // displays 13.0
![Page 77: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/77.jpg)
A Closer Look at the A Closer Look at the %% OperatorOperator% (modulus) operator computes
the remainder resulting from integer division
cout << 13 % 5; // displays 3
% requires integers for both operands
cout << 13 % 5.0; // error
![Page 78: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/78.jpg)
2.152.15Comments
![Page 79: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/79.jpg)
CommentsCommentsUsed to document parts of the
programIntended for persons reading the
source code of the program:◦Indicate the purpose of the program◦Describe the use of variables◦Explain complex sections of code
Are ignored by the compiler
![Page 80: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/80.jpg)
Single-Line CommentsSingle-Line Comments
Begin with // through to the end of line:int length = 12; // length in inchesint width = 15; // width in inchesint area; // calculated area
// calculate rectangle areaarea = length * width;
![Page 81: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/81.jpg)
Multi-Line CommentsMulti-Line CommentsBegin with /*, end with */Can span multiple lines:/* this is a multi-line comment*/
Can begin and end on the same line:int area; /* calculated area */
![Page 82: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/82.jpg)
Comment Guidelines – how Comment Guidelines – how muchmuchFor you, a beginning
programmer, I suggest MORE is better
Explain algorithms, formulas, variables that you are using
Explain with enough detail that someone who did NOT write the code and is a beginning programmer could understand it
![Page 83: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/83.jpg)
Comment Guidelines --Comment Guidelines --wherewhereTowards the top of your programBefore every function you createBefore loops and test conditionsNext to declared variables.
![Page 84: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/84.jpg)
2.162.16Named Constants
![Page 85: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/85.jpg)
Named ConstantsNamed ConstantsNamed constant (constant
variable): variable whose content cannot be changed during program execution
Used for representing constant values with descriptive names:const double TAX_RATE = 0.0675;const int NUM_STATES = 50;
Often named in uppercase letters
![Page 86: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/86.jpg)
Named Constants in Program Named Constants in Program 2-282-28
![Page 87: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/87.jpg)
2.172.17Programming Style
![Page 88: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/88.jpg)
Programming StyleProgramming StyleThe visual organization of the
source codeIncludes the use of spaces, tabs,
and blank linesDoes not affect the syntax of the
programAffects the readability of the
source code
![Page 89: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/89.jpg)
Programming StyleProgramming StyleCommon elements to improve
readability:Braces { } aligned verticallyIndentation of statements within
a set of bracesBlank lines between declaration
and other statementsLong statements wrapped over
multiple lines with aligned operators
![Page 90: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/90.jpg)
2.182.18Standard and Prestandard C++
![Page 91: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/91.jpg)
Standard and Prestandard Standard and Prestandard C++C++Older-style C++ programs:
◦Use .h at end of header files:◦ #include <iostream.h>◦Use #define preprocessor directive
instead of const definitions◦Do not use using namespace
convention◦May not compile with a standard C+
+ compiler
![Page 92: Introduction to C++. 2.1 The Parts of a C++ Program –Anatomy of a simple C++ program](https://reader035.vdocument.in/reader035/viewer/2022062517/56649ed25503460f94be1792/html5/thumbnails/92.jpg)
#define#define directive in Program directive in Program 2-312-31