Comments and Keyword

C++ Comments:

Comments allow programmers to make the code more understandable and readable.

With the help of comments, vital information about the corresponding line of code is written, so that even a non-programmer can understand the logic used.

Every programming language supports some form of comments, C++ supports two types of comments, and these are:

• Single – Line Comments
• Multi-Line Comments

 

1. Single – Line Comments:

A Single – Line C++ comment starts with //

For example: 

#include <iostream> 
void main() 
{ 
cout << "Hello World"; // prints Hello World 
return 0; 
}

When the above code is compiled, it will ignore

 // prints Hello World 

And final executable code will produce the following result: 

Hello World

However, a Single – Line C++ comment spans only to a single line, so if you write anything like this, then it will not be a comment: 

// C++ Comment Line 1
Line 2

Here, Line 2 is not treated as a comment, but as an executable C++ statement. 

 

2. Multi-Line Comments:

Multi-Line C++ comments start with /* and end with */

For example: 

/* This is a comment */ 
/*Multi – Line C++ comments can also 
Span in multiple lines 
*/

Here, everything written between the starting (/*) and ending (*/) symbols is treated as a C++ comment.

The C++ compiler ignores everything written within the comments, thus it is never executed.

 

C++ Keywords:

Keywords are the words that cannot be used as the names for any constant, variable or an identifier in C++.

It is so because these words already have some predefined meaning to the C++ compiler.

The C++ Keywords are:

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