Learning C++ :Chapter 4

CHAPTER 4 
Hello Everyone. Today I will teach you about the R-Value and L-Value OF Variables and About Escape Sequences and How to use them ?


R-Value And L-Value
R-Value refers to the content or data value of the variable whereas The L value (Location Value) represents the address or location of the variable.


Here I want to give an example: Variable A is Taken which has been assigned value 17 and It is in 2004.Here 17 is the R-Value and 2004 is L-value (also called as Location Value).


ESCAPE SEQUENCES


It is also called non-graphic characters that have special meaning for the compiler.
FEATURES:

• It always start with the \ (slash).
• It is only used within the double quotes.(").
• We can only use them in cout  statements.

There are following escape sequences:
\a
It stands for audible sound.It will produce an audible sound with the help of the sound card attached in the motherboard.
\n
It stands for new-line character.As it is the feature of C++ to display all the contents in the single line so we can use \n to take the text to the next line.
\v
It stands for vertical tap.It provides vertical spaces but in the output window there will be no any difference as \v is only applicable at the time of printing.
\t 
It stands for horizontal tap.It provides few spaces in horizontal direction.
Example: " Hello                 World"
\r
It is the escape sequence that places the cursor at the begging of the line.
Example: cout<<"Welcome \r here";
Output will be  :          hereome

SO friends do try these escape sequences and if any doubt arises post it in comments or send @ ishu.hitesh@gmail.com

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Learning C++ :Chapter 3

Chapter 3

Hey friends Today on Technomantras I want to give the chapter 3 of C++ .in this chapter we will study about the  concept of variables and how to initialize and declare them ? 

VARIABLE

variable is simply the name of the memory where we can store data.

For example:

#include<iostream.h>

#include<conio.h>

void main( )

{

clrscr( );

int a=10;

cout<<a;

getch( );

}

In the above program "a" is a variable that is assigned the value 25.I hope you people are clear about the meaning of variables.

Now the next concept is how to declare them and initialise them??

DECLARATION

It means simply declaring the variable such as in the above program I have declared A as a variable.

INITIALIZING

It means giving value to the variable.In the above Program the value given to a is 25.It is called Initializing. 


Declare and initialise the variables as:

int a=10;

 -----OR-----
int a;
a=10;

IMP. CONCEPTS REGARDING VARIABLES

1.Don't use space in the name of variables.

2.Variable name cannot start with a number but number can be part of the variable.

3.Underscore(_) can be used in the variable name.

4.The variable name should be logical.

5.At a time variable save only one value.

6.The variable names cannot be same even if the data types are different.

7.In case if user doesn't give any value to the variable then the variable is assigned a garbage value by the system.

For Eg.

Try 

int a;

cout<<a;

System will provide some garbage value to the variable.

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Learning C++ : Chapter 2

CHAPTER 2


Hello Friends ..Today we will begin with chapter 2 of C++.In this chapter I will tell you that What are header files and What is the structure of C++ Code:



HEADER FILES


In the last chapter we discussed about IOSTREAM.H and CONIO.H.Now what are they? These are the header files. Header files can be defined as the external files that contains reference of different inbuilt functions of C++.All the inbuilt functions are collection of instructions and these functions are defined in header files.


STRUCTURE OF C++ PROGRAM
In this block we use a system function main( ). Note that the main is only function after which we don't use semicolon; . Main is the entry point of the program.The compilation of the program will start from here.




-----Header files----


void main( );
{


CODING OF C++ PROGRAM


}


SOME IMPORTANT TERMS


1. CHARACTER SET :
The valid characters used in c++ program is called character set.
In C++ we can use 256 characters such as Digits(0-9)
Alphabets(A-Z,a-z) and other special symbols.


2.KEYWORDS
These are the special words used in C++ that has special meaning for the compiler.For example: clrscr( ); getch( )


3.IDENTIFIERS
Any user defined word is called an Identifier.It may be variable name,class name and function name.

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Learning C++ :Chapter 1

CHAPTER 1
C++ language was developed by Bjarne Stroutstrup. It called the language as " C with classes".So this language was given the name " C++ ".


IMPORTANT FEATURES:

• C++ language uses classes.
• The extension of C++ file is .cpp
• C++ language is case sensetive.
• Compiler is used in C++ to compile the program.
• Three files are created after compiling program: .cpp .obj and .exe

Now this was only about the developer of C++.
Now lets begin with programming.Programming refers to creating programs which afterwards are combined to form a software.


Now we should start with Just a Simple C++ Program:


Type in your Computers
:
#include<iostream.h>
#include<conio.h>
void main( )
{
clrscr( );
cout<<"Hello World";
getch( );
}

Now lets find out what does this program displays:


Hello World




In this program:
#include<iostream.h> and #include<conio.h>  are the two header files which contain the functions (predefined) .In this program COUT function is a prototype of IOSTREAM.H and GETCH is the prototype of CONIO.H 


clrscr( ); is used to clear the screen.It is the prototype of Conio.h
cout refers to CONSOLE OUTPUT. It is used to display the required data.Such as in this case we have displayed "Hello World".




Now I think You are clear enough about what is C++ and how programming  begins.


Please Visit: C++ beginners  section for Second Lesson

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For C++ Learners: Run C++ in Windows 7 (Full Screen)

Many people generally ask "Can We run C++ in full screen mode in Windows 7?". For us running C++ in a small window..becomes irritating as sometimes we don't type the right command and thus it becomes frustrating. Earlier I also didn't had nay answer..but now ..I have got a software from which we can run C++ in Full screen mode in Windows 7.

You can Download the Emulated C++ version from here: 

Click To Download

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