FOP : Chapter 2

Chapter 2 : C++ Basics

The C++ language consist of two elements : Semantics and Syntax 

• Semantics is a vocabulary of commands that humans can understand and that can be converted into machine language. Table below shows a partial list of vocabulary use in C++ program programming that are also referred to as keywords or reserved word.
• Syntax is a language structures (or grammar) that allow humans to combine these C++ commands into a program that actually does something.

Example : 

Cout<<”Hello World.”;       (Correct C++ statement) =Correct Syntax
c Output “Hello World”.     (Incorrect C++ statement) = Wrong Syntax

This are the keywords/reserved word :

asm	do	inline	short	typeid
auto	double	int	signed	typename
bool	dynamic_cast	log	sizeof	union
break	else	mutable	static	unsigned
case	enum	namespace	static_cast	using
catch	explicit	new	struct	virtual
char	extern	operator	switch	void
class	false	private	template	volatile
const	float	protected	this	wchar_t
const_cast	for	public	throw	while
continue	friend	register	true
default	goto	reinterpret_cast	try
delete	if	return	typedef

A simple example C++ program :

#include <iostream>

using namespace std;

int main()

{

        cout << "Welcome to the wonderful world of C++!!!\n";

        return 0;

}

Here is an example of running the program:

Welcome to the wonderful world of C++!!!

• A C++ application program is formed by many components that are comments, the include directive and header files, functions, declarations, reserved words, console input/output, escape sequences and statements.

Components	Summary	Example
Comments	Comments are non-executing statements that you add to a program for purpose of documentation.	// One line statements /* Multiple    line    statements */
The preprocessor directive and header file	The preprocessor directive enables the program to use certain functions contained in the external file.	#include <iostream.h> #include <math.h>
Functions	Functions are the basic building block in C++.	Main() {     // Statements }
Declarations	All variables used in a C++ program must be declared before their use. Variables are simply reference to memory locations.	int x, y, sum;
Reserved words	Reserved words used in the C++ language have special meaning and they cannot be used for any other purpose.	Include, int, main, return
Escape sequences	An escape sequence always begins with the backslash (/) and is followed by one letter or special character.	\n, \t, \\, \”, \’
Console input & output	Data are entered into the computer using cin (console input) and the redirection operator     >>. The function cout and the redirection operator   << sends the output to the system   console.	cout<”Enter a number: “; cin>>num;
C++ statements	Executable statements in C++ must be followed by a semicolon.	Int x, y, sum; cout<”Enter a number: “; cin>>x; sum = x + y;