Basics Of C++.

Introduction....

History....
C++programming language was developed at 'AT&T BELL LABORATORIES'.In 1979 BJARNE STROUSTRUP was studying for his PH.D thesis. Simula 67 was a programming language which was designed for simulations and one of the first language which supported the object oriented programming paradigm.

He found 'C' lacking simulations and decided to extend the language by inserting some of his favoritefeatures from languageSimula 67 to it his goals was to insert features like inheritance,in-liningetc to a well known language which is famous for its probabilitywithout sacrificing speed and low level functionality.The name of C++ was coined by Rick Mascitti where "++" is used as an increment operator which is used to increase a value to "that + 1".The latest C++ standards document was issued by ANSI/ISO in 2011 namely "C++11" or formally "C++0x". A picture may help to figure out more.

C++ CHARACTER SET....

Characterset is a set of characters which used to represent information.

LETTERS:-A-Z,a-z.

DIGITS:-0-9.

SPECIAL SYMBOLS:-=,+,@,!,#,^,&.....

WHITE SPACES:-Blank space,tabs,carriage return,newline etc....

Others:-The other left out elements.

TOKENS....

Also known as lexical units and the smallest units of a program.These are:-

Keywords:-These are those words which convey special meaning, their purpose is reserved and cannot be used as normalidentifiers.Likecontinue,float,delete etc....

Identifiers.:-These are used to give names to different parts of a program like a function or a constant etc.And first letter should be a letter or an underscore"_".Both uppercase and lower case are valid.Like My_file,a_b_c,d_e_f etc...

Literals:-Thesenever change their value during execution i.e they are constants.these are:-

Bool:-These show a value either as a true '1'or false '0'.

Integer:-These are those constants which represent whole numbers withoutfractionalpart where the rules to create it are:-

1.These should not have have decimal point2.these should have at leastone digits.3.these can have + or - sign.4.without any sign it is assumed to be a + sign.5.these should not have blanks and commas.

These are of three types:-
*Decimal:-These are normal numbers like in human world.
like 1,2,123,4522,-898,+2333.
*Octal:-These start with a zero like 010,014 etc....
*Hexadecimal:-these are preceded by "0X" like 0x,0xc etc.

Character:-These are enclosed in single' '.These have numerical value in ASCII codes.Like:-'a','1','@'etc.Where there are many non-graphic characters also which are called escape sequences precedes by '\' these imply an escape from the normal interpretation of a line for ex:'\\',\r' etc.

Floating:-These are also called real constants.These have fractionalparts.And can be written in two forms fractional and exponential form in which factional form are always declared as the normal decimal point numbers like in human world like +13.5,-17.9 etc.where exponent have two partsmantissawhich is a part before 'e' andexponentwhich is a part after'e'like 123.e5,067.e7 etc.

String:-These are sequence of characterssurrounded by double" ".And these are always terminated with "\0" {null character}which always extend its size to one more character{usually represents as array of characters.

Punctuators:-Theserepresenta particular function to be performed likesemicolon";" is used to terminate astatement.

Operators:-These are used to gain results after performing an operation on two values like a+b,a\c etc.Types of operators are:-

1.Binary:-These operate upon two operands{values}.types of binary operator are:-

*Arithmeticoperators:-used to perform arithmeticoperations like +,-,\,* etc.
*Assignment:-These are used to assign the value of one expression to another variable like =,/=,*= etc.

*Relational:-These are used to recognizethat one condition turn out to be true '1',false '0'.like <,> etc.

*Logical :-These are used to make logical operations like &&,||,!.
*Class member:-These are used with classes like ::,.* etc.
2.Unaryoperators:-These operateupon single operand.
*Bit wise operators:-These operate upon bit levels like &,^,| etc. OR ++,--, etc which are used to increment , decrementa value respectively and - is use to make a valuenegative.

3.Ternary:-It operate uponthree operands and there is a conditional operator only in this category.

HELLO WORLD PROGRAM....

#include<iostream.h>// This is a pre-processordirective indicated by'# include' and then a header file which contains cout and cin normally used to input and output our data on screen.{this is a comment on which usual compiler rules doesn't get applied}

using namespace std;
int main()//this isa mainfunction or we can call it as driver function .The execution of a programalwaysstarts with this function

{
cout<<"Hello World";//it will print out data .
return 0;//it will return a 0 as indicating a successful termination of the main function as its return value is int like 'int'main().

}

OUTPUT:-