p2 introduction to c

8/3/2019 p2 Introduction to c

1/35

2/15/20122/15/2012 11


2/35

2/15/20122/15/2012 22

OverviewOverview

Developed by Dennis Ritchie at AT & T

Bell Laboratories in 1992

Reliable, simple and easy to use

Top-down programming


3/35

2/15/20122/15/2012 33

Why CWhy C

C has been already superceded by

languages like C++, C# and Java, so why

bother to learn C today?


4/35

2/15/20122/15/2012 44

Why CWhy C

Reasons

No body can learn C++ or Java directly, the

basic programming elements are learned from

C

C++ and Java tools frameworks are still built

on C only

Major part of popular Operating Systems likeUnix, Linux and Windows are written inC


5/35

2/15/20122/15/2012 55

Why CWhy C

Reasons

When it comes to performance in terms of

execution speed nothing beats C

Device drivers are commonly written in C

In case embedded systems like mobiles and

palmtops the programs not only have to run

fast but also have to work in limited memory.C is the best language in choice with these

constraints on time and space.


6/35

2/15/20122/15/2012 66

SyllabusSyllabus -- C programmingC programming

Storage Classes, Data Types, Controllingprogram flow, arrays, functions, MemoryManagement

Pointers, Arrays and pointers, Pointer tofunctions and advanced topics on pointers,Structures and unions, Data structures

Linked List, Stacks, Queues, Conditional

Compilation, Preprocessor directives, Fileoperations, Variable arguments in Functions,Command line arguments, Bitwise operations,Typecasting


7/35

2/15/20122/15/2012 77

Structure of a C ProgramStructure of a C Program

Preprocessor Commands

Type definitions

Function prototypes - declare functiontypes and variables passed to function.

Variables

Functions (main() function-Must)


8/35

2/15/20122/15/2012 88

Character Set Alphabets, Digits and Special symbols


9/35

2/15/20122/15/2012 99

Constants, Variables and KeywordsConstants, Variables and Keywords

Alphabets

Numbers

Special Symbols

Constants

Variables

Keywords

Constant - Entity that doesnt change

Variable Entity that may change


10/35

2/15/20122/15/2012 1010

Types of ConstantsTypes of Constants


11/35

2/15/20122/15/2012 1111

Primary ConstantPrimary Constant --IntegerInteger

Must have atleast one digit

Must not have a decimal point

Can be either positive or negative By default, positive

No commas or blanks allowed within the

integer constant Range is -32768 to 32767

Ex.: 426,+400,-324,-3287


12/35

2/15/20122/15/2012 1212

Primary ConstantPrimary Constant--RealReal

Must have atleast one digit

Must have a decimal point

Could be positive or negative By default, positive

No commas or blanks are allowed within a

real constantEx. : +325.34,467.0,-67.54,-12.675


13/35

2/15/20122/15/2012 1313

Primary ConstantPrimary Constant--RealReal

Exponential form of representationmantissa e exponent

Mantissa and Exponential should be separated

by a letter e

Mantissa may have a positive or negative sign

By default, mantissa sign is positive

Exponent must have atleast one digit, can be

positive or negative and by default it is positive Range is -3.4e38 to +3.4e38

Ex.: +3.2e-5,12.1e18, -0.7e+5, -3.2e-5


14/35

2/15/20122/15/2012 1414

Primary ConstantPrimary Constant--CharacterCharacter

Can be a single alphabet, single digit or a

single special symbol enclosed within a

single inverted commas. Both the inverted

commas should point to the left.

A is a valid character whereas A is not.

Maximum length can be one character.

Ex. : 'A' , 'I' , '5'


15/35

2/15/20122/15/2012 1515

Primary Data typesPrimary Data types

Integerlong

short

signed

Unsigned

CharSigned

Unsigned

Floats and Doubles


16/35

2/15/20122/15/2012 1616

Note: use sizeof() function to check the bytes occupied by the data types


17/35

2/15/20122/15/2012 1717

Types of C VariablesTypes of C Variables

Particular type of variable can hold only

the same type of constant.

Integer variable holds only integerconstant

Rules for constructing different types of

constant varies whereas for constructing

variable names of all types the same set of

rules apply.


18/35

2/15/20122/15/2012 1818

Rules for constructing variable namesRules for constructing variable names

Variable name is combination of 1 to 31alphabets, digits or underscores.

Maximum length is 31 characters

First character must be an alphabet orunderscore

No commas or blanks allowed

No special symbol other than anunderscore can be used.

Ex. : si_int , m_hra , si_intr_2008


19/35

2/15/20122/15/2012 1919

Rules for constructing variable namesRules for constructing variable names

It is compulsory to declare the type ofvariable before use in the program. This

type declaration is done at the beginning.

Example of type declaration.int si, m_hra ;

float bassal ;

char code ;


20/35

2/15/20122/15/2012 2020

C KeywordsC Keywords

Words whose meaning has already been

explained to the compiler

Cannot be as variable names


21/35

2/15/20122/15/2012 2121

FIRST C PROGRAMFIRST C PROGRAM

main( ){

int p, n ;

float r, si ;

p = 1000 ;

n = 3 ;

r = 8.5 ;

si = p * n * r / 100 ; /* formula for simple interest */

printf ( "%f" , si ) ;

}


22/35

2/15/20122/15/2012 2222

Rules for writing a programRules for writing a program

Every C statement must end with a ; ,

which acts as a terminator

All statements are entered in small letters Comment about the program should be

enclosed with /* */.

Printf function is used to display value inthe screen.


23/35

2/15/20122/15/2012 2323

Printf() functionPrintf() function

It is defined in stdio library.

General form of printf() function is,

printf("" ,); Table represents the list of format strings

used in C.

Escape sequences are also used in printfto cause an escape from normal

interpretation of string.


24/35

2/15/20122/15/2012 2424


25/35

2/15/20122/15/2012 2525

Printf() functionPrintf() function

some examples of usage ofprintf( )

function:

printf ( "%f", si ) ;

printf ( "%d %d %f %f", p, n, r, si ) ;

printf ( "Simple interest = Rs. %f", si ) ;

printf ( "Prin = %d \nRate = %f", p, r ) ;


26/35

2/15/20122/15/2012 2626

Escape SequencesEscape Sequences


27/35

2/15/20122/15/2012 2727

Scanf() functionScanf() function

To enter the data from the keyboard

during run-time.

scanf ( "format string", list of addresses ofvariables ) ;

Example:scanf ( "%d %f %c", &c, &a, &ch ) ;


28/35

2/15/20122/15/2012 2828

Scanf() functionScanf() function

We are sending addresses of variable to

scanf() function.

Values received from the keyboard mustbe dropped into variables corresponding to

these addresses.


29/35

2/15/20122/15/2012 2929

C InstructionsC Instructions

Three type of instructions in C.

Type Declaration Instruction-To declare the type ofvariable used in C program

Arithmetic Instruction-To perform arithmetic

operations between constants and variables

Control Instruction-To control the sequence of

execution of various statements in C program


30/35

2/15/20122/15/2012 3030

Type Declaration InstructionType Declaration Instruction

Used to declare the type of variable usedin the program and written at the

beginning of main() function.

While declaring variable, we can alsoInitialize.

int i=10,j=25;

Order of definition matters in some cases.int i = 10, j = 25 ; is same as int j = 25, j = 10 ;

float a = 1.5, b = a + 3.1 ; is alright, but float b = a + 3.1, a = 1.5 ; is not.

int a, b, c, d ; a = b = c = 10 ; will work,int a = b = c = d = 10 ; will not.


31/35

2/15/20122/15/2012 3131

Arithmetic InstructionArithmetic Instruction

Consists of variable name on the left hand

side of =,variable name and constants on

the right hand side of the equal.

Variables and constants appearing on the

right hand side of the equal are connected

by arithmetic operators like +,-,* and /.

Arithmetic statement could be of three

types.


32/35

2/15/20122/15/2012 3232

Arithmetic StatementArithmetic Statement

Integer mode-operands are integer

variables and integer constants.

Real mode-operands are real variables

and real constants

Mixed mode-some of the operands are

real and some of them are integers.

Ex. : float si, prin, anoy, roi, avg ;int a, b, c, num ;

si = prin * anoy * roi / 100.0 ;

avg = ( a + b + c + num ) / 4 ;


33/35

2/15/20122/15/2012 3333

CompilersCompilers

GCC from Linux

Turbo C

Ansi C Visual C


34/35

I request Electronics and communication

ENGINEERING students to visit my blog

for more

abhishek1ek.blogspot.com

awhengineering.blogspot.com u can also email me

[email protected] for more ppt

2/15/20122/15/2012 3434


35/35

2/15/20122/15/2012 3535

p2 introduction to c

Documents