PROGRAMMING LANGUAGE:

> Much in the same way when a user wants to communicate with a computer ,the language that he/she uses for this purpose is known as programming language .

>Like BASIC,COBOL,C,C++,JAVA……

>At the same time we know that computer understands only one language that is MACHINE LANGUAGE .

>This language includes only 0&1.It’s very difficult for us to learn this language.

TYPES OF PROGRAMMING LANGUAGE:

>Basically there are two types of programming languages.

1. Low Level Language = Machine Language , Assembly Language
2. High Level Language = c , c++ , JAVA , C#

PROGRAMMING

C IS MIDDLE-LEVEL LANGUAGE:

>C stands in between these two categories.

>Since it was designed to have both:

>A relatively good programming efficiency as compared to Machine Oriented Languages.

APPLICATION AREAS OF C:

1. C was initially used for systems programming.

2. A system program forms a portion of the operating system of the computer or its support utilities.

3. The UNIX operating system was developed using C.

4. Operating Systems, Interpreters, Editors, Assembly programs are usually called system programs.

COMPILATION AND EXECUTION OF A PROGRAM:

C SOURCE CODE >C PREPROCESSOR > EXPANDED C SOURCE CODE> C COMPILER > TARGET ASSEMBLY CODE>LINKER>EXECUTABLE CODE>LOADER>OUTPUT

TERMINOLOGIES OF “C”:

1. Keywords
2. Identifiers
3. Variables
4. Constants
5. Special Symbols
6. Operators
7. Character & String

KEYWORDS:

Keywords are predefined, reserved words used in programming that have special meanings to the compiler. Keywords are part of the syntax and they cannot be used as an identifier. For example:

int money;

KEYWORD

Here, int is a keyword that indicates money is a variable of type int (integer).

As C is a case sensitive language, all keywords must be written in lowercase.

IDENTIFIERS:

Identifier refers to name given to entities such as variables, functions, structures etc.

Identifiers must be unique. They are created to give a unique name to an entity to identify it during the execution of the program. For example:

int money;
double accountBalance;

Here, money and accountBalance are identifiers.

Also remember, identifier names must be different from keywords. You cannot use int as an identifier because int is a keyword.

Rules for naming identifiers

1. A valid identifier can have letters (both uppercase and lowercase letters), digits, and underscores.
2. The first letter of an identifier should be either a letter or an underscore.
3. You cannot use keywords as identifiers.
4. There is no rule on how long an identifier can be. However, you may run into problems in some compilers if the identifier is longer than 31 characters.

You can choose any name as an identifier if you follow the above rule, however, give meaningful names to identifiers that make sense.

CONSTANTS:

Constants are like a variable, except that their value never changes during execution once defined. … Constants in C are the fixed values that are used in a program, and its value remains the same during the entire execution of the program. Constants are also called literals. Constants can be any of the data types.

CONSTANTS

SPECIAL SYMBOLS:

$= Dollar sign

%= Percent sign

&= Ampersand

*= Asterisk

_= Underscore

= Plus sign

\= Backslash