introduction to c++

contents

review
c++
c++ standard library
se observations
compiled programs
data hierarchy
key se concepts supported by oo languages
c++ syntax
escape sequences
return statements
variable declarations, definitions like c
relational operators
if statements
assignment operators
increment and decrement operators
keywords
control structures
if selection statements
if...else double selection statements
another if...else example
block and null statements
while statements
for statements
do...while statements
switch statements
case statements
break statements
continue statements
logical operators
operator precedence
structured programming
the math library
function prototypes
function signatures
function headers
storage classes
scope rules
function call stack
functions with no parameters
inline functions
reference parameters
default arguments
unary scope resolution operator
function overloading
function templates
data types in c++
object-orientation in c++
class and object definitions
public and private members
initializing class objects

review

c programming

basic data types
control structures
arrays

c++

c++ a powerful computer programming language that’s appropriate for technically oriented people with little or no programming experience, and for experienced programmers to use in building substantial information systems
c++ is one of today’s most popular software development languages
c++ evolved from c, which was developed by Dennis Ritchie at Bell Laboratories – c++, an extension of c, was developed by Bjarne Stroustrup in 1979 at Bell Laboratories – c++ provides several features that “spruce up” the c language

c++ standard library

c++ programs consist of pieces called classes and functions
most c++ programmers take advantage of the rich collectiosn of classes and functions in the standard library
two parts of learning the c++ world
- the c++ langauge itself
- how to use the classes and functions in the c++ standard library
many special-purpose class libraries are supplied by independent software vendors

se observations

use a "building-block" approach to create programs. avoid reinventing the wheel. use existing pieces whenever possible. called software reuse, this practice is central to object-oriented programming.
when programming in c++, you typically will use the following building blocks, classes and functions from the c++ standard library, classes and function you and your colleagues create and classes and functions from various popular third-parties libraries.
using c++ standard library functions and classes instead of writing your own version can imporve program perforamce, because they're written carefully to perform efficiently. this technique also shortens program development time.

compiled programs

compiling a high-level language program into machine language can take a considerable amount of computer time
interpreter programs were developed to execute high- level language programs directly (without the need for compilation), although more slowly than compiled programs
scripting languages such as the popular web languages JavaScript and PHP are processed by interpreters

examples of indusry software that uses c++

microsoft visual studio
adobe photoshop
google chrome
apple xcode
microsoft office
call of duty
amazon's e-commerce platform
grand theft auto
financial trading software such as metatrader
the XRP ledger - decentralized blockchain that supports the XRP cryptocurrency

data hierarchy

[][][][]
[][][][]  <- file
[][][][]

[][][] <- record
[][][]
[][][]

[][]  <- field
[][]

[]  <- byte (ASCII character)

1 <- bit

key se concepts supported by oo languages

abstraction
classes
- attributes and methods
- member functions
- public, private, or protected
encapsulation
- information hiding
- single, double
- faciliate reusability
polymorphism
- overloading
- overriding

c++ syntax

// indicates a comment; and extends to the end of the line
can still use /*...*/ combination
a # directive is a message to the preprocessor
#include <iostream> is for i/o
like C, white spaces are ignored
main() function is part fo every C++
c++ programs being executed at function main()
the rest of the program consists of classes and functions
typically, output and input in c++ are accomplished with streams and characters
when a cout statement executed, it sends a stream of characters to the standard output stream object std::cout which is normally connected to the screen
the names cin (the standard input stream) and cerr (the standard error stream) also belong to namespace std

std::cout << "string literal output\n";

the << operator is referred to as the stream insertion operator
the value to the operator's right is inserted in the output stream
the escape sequence \n means new line character and causes the cursor to move to the beginning of the next line on the screen
using multiple stream insertion operators << in a single statement is referred to as concatenating, chaining, or cascading stream insertion operators

escape sequences

\n newline
\t horizontal tab
\r carriage return
\a alert
\\ backslash character
\' single quote
\" double quote

return statements

when the return statement is used at the end of main the value 0 indicates that the program has terminated successfully
according to the c++ standard, if program execution reaches the end of main without encountering a return statement, it's assumed that the program terminated successfully

variable declarations, definitions like c

fundamental types are like c and are all lowercase
short, int, long, double, char
identifiers (variables, function names,...) also like c
assignment operators also like in c: +, -, *, /, %

relational operators

if statements

assignment operators

increment and decrement operators

keywords

control structures

if selection statements

if...else double selection statements

another if...else example

block and null statements

while statements

for statements

do...while statements

switch statements

case statements

break statements

continue statements

logical operators

operator precedence

structured programming

the math library

function prototypes

function signatures

function headers

storage classes

scope rules

function call stack

functions with no parameters

inline functions

reference parameters

default arguments

unary scope resolution operator

function overloading

c++ enables several functions of the same name to be defined, as long as they have different signatures
the c++ compiler selects the proper function to call by examining the number, types, and order of the arguments in the call
function overloading is used to create several functions of the same name that perform similar tasks, but on different data types

function templates

if the program logic and operator are identifical for each data type, overloading may be performed more compactly and convently by using function templates
you write a single function template definition
all function template definitions begin with the template keyword followed by a template parameter list to the function template enclosed in angle brackets < and >

data types in c++

char - unsigned char, 8-bit integer
short unsigned short - 16-bit integer
int - unsiged int - 32-bit integer
long - unsigned long - 64-bit integer
bool - n/a - true or false
float - 32-bit floating point
double - 64-bit floating point
long long - 128-bit integer

type casting

c++ is stringly typed; it will auto-convert a variable of one type to another in a limited fashion (wont change the value)

short x = 1;
int y = x;		// OK
short z = y;	// NO

object-orientation in c++

classes

defines a set of data items and structures (data members)
defines a set of operations (operation members)
also called methods (functions)
also called services
also called class behavior
encapsulates the two
indicates which of the above members are accessible (public) and which are inacccessible (private)
- use of access specifier: public, private, protected
class defines an abstract data type
examples: course, student, teacher, book, account, printer

add UML - Unified modeling language

class Student {
	public:
		int getAge();
		std::string getName();
	private:
		int myAge;
		std::string myName();
}

class and object definitions

class

class Box {
	private:
		// data members
	public:
		// member functions
};

objects

Box b1;
Box b2;
Box b3;

public and private members

member access specifiers

classes can be limit the access to their member functions and data
the three types of access a class can grant
public accessible wherever the program has access to an object of the class
private accessibe only to member functions of the class
protected similar to private; discussed later

the constructor and destructor methods

the constructor function

a special member function that initializes the data members of a class object
cannot return values
the same name as the class

the destructor function

a special function with the same name as the class but preceded with a tilde character ~
cannot take arguments and cannot be overloaded
performs termination housekeeping

accessing class members

. for objects
-> for pointers
assume an object t

t.hour
t.printMilitary();

initializing class objects

constructors
- initialize class members
- same name as the class
- no return type
- member variables can be initialized by the constructor or set afterward
passing arguments to a constructor
- when an object of a class is declared; initializers can be provided
- format of declaration with initializers
- default arguments may also be specified in the constructor prototype

class-type objectname(datat-type value1, data-type value2);

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