C++ Basic Syntax

Definition:-

When we consider a C++ program, it can be defined as a collection of objects that communicate via invoking each other's methods. Let us now briefly look into what a class, object, methods, and instant variables mean.

·        Object − Objects have states and behaviors. Example: A dog has states - color, name, breed as well as behaviors - wagging, barking, eating. An object is an instance of a class.

·        Class − A class can be defined as a template/blueprint that describes the behaviors/states that object of its type support.

·        Methods − A method is basically a behavior. A class can contain many methods. It is in methods where the logics are written, data is manipulated and all the actions are executed.

·        Instance Variables − Each object has its unique set of instance variables. An object's state is created by the values assigned to these instance variables.

C++ Program Structure :-

Let us look at a simple code that would print the words Hello I am A Programmer.

#include <iostream>

using namespace std;

// main () is where program execution beings.

int main() {

cout << “Hello I am a programmer.”; // prints Hello I am A Programmer.

     return 0;

}

·        The C++ language defines several headers, which contain information that is either necessary or useful to your program. For this program, the header <iostream> is needed.

·        The line using namespace std; tells the compiler to use the std namespace. Namespaces are a relatively recent addition to C++.

·        The next line '// main() is where program execution begins.' is a single-line comment available in C++. Single-line comments begin with // and stop at the end of the line.

·        The line int main() is the main function where program execution begins.

·        The next line cout << "This is my first C++ program."; causes the message "This is my first C++ program" to be displayed on the screen.

·        The next line return 0; terminates main( )function and causes it to return the value 0 to the calling process.

Semicolons and Blocks in C++ :-

In C++, the semicolon is a statement terminator. That is, each individual statement must be ended with a semicolon. It indicates the end of one logical entity.

For example, following are three different statements –

x = y;

y = y + 1;

add(x, y);

C++ does not recognize the end of the line as a terminator. For this reason, it does not matter where you put a statement in a line. For example −

x = y;

y = y + 1;

add(x, y);

is the same as

x = y; y = y + 1; add(x, y);

C++ Identifiers :-

A C++ identifier is a name used to identify a variable, function, class, module, or any other user-defined item. An identifier starts with a letter A to Z or a to z or an underscore (_) followed by zero or more letters, underscores, and digits (0 to 9).

C++ does not allow punctuation characters such as @, $, and % within identifiers. C++ is a case-sensitive programming language. Thus, Manpower and manpower are two different identifiers in C++.

C++ Keywords :-

The following list shows the reserved words in C++. These reserved words may not be used as constant or variable or any other identifier names.

asm	else	New	This
auto	Enum	Operator	Throw
bool	explicit	Private	True
break	Export	Protected	Try
case	Extern	Public	Typedef
catch	False	Register	Typeid
char	Float	reinterpret_cast	typename
class	For	Return	Union
const	Friend	Short	Unsigned
const_cast	Goto	Signed	Using
continue	If	Sizeof	Virtual
default	Inline	Static	Void
delete	Int	static_cast	volatile
do	Long	Struct	wchar_t
double	mutable	Switch	while
dynamic_cast	namespace	Template

Thank You!