UNIT-2Programming language 'C'

Contents

Types of Programming Languages : 1. Machine-level,2. Assembly,3. High level languages.

Features of C : basic concepts, structure of a C program, declarations,

Data types : Variables, expressions, conditional expressions.

Operators : Assignment, Arithmetic, Relational, Logical, Increment and Decrement, Precedence of operators, Type conversions,

I/O Function : scanf and printf functions.

Programming Language

A programming lang. is the lang. used tocommunicate instructions to the machine i.e.Computer.

Ex. C, C++, Basic, Cobol, Pascal Fortran.JAVA, JAVA Script.VB, VB .NETPHPC#PythonSQL

Types of Programming Languages

1. Machine-level Languages2. Assembly Languages3. High level Languages

Machine-level or Low Level Languages

series of sequence of 1 & 0 as instructions.This is the only lang. understand by computer.

These are machine dependent lang.Machine language instructions has two parts

1. Opcode ( Operation Code):Tells the computer which operation to perform.2. Operand : It tells where to find or store the

data to be manipulated.

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Advantages Of Machine Languages

Only languages understand by computerSimply understandable for computerIt does not require any translator to translate

code.Limitation Of Machine Languages

Difficult for userAll opcode and addresses must rememberError finding is difficult as it is written in 0&1Writing program it takes huge time.

Assembly Language

Low Level programming developed to overcomeinconveniences of machine lang.

In assembly lang. operation codes and operands aregiven in the form of alphanumeric symbols insteadof binary nos. 1&0. These symbols are also called asmnemonic codes.

This is also machine dependent.Assembly language programming Are translated into

executable machine code by using assembler.

Assembly language program

AssemblerMachine Code (Object Code)

Assembly Language Program

High Level Lang

Designed to enable people to write program Easily& in their own native lang. i.e. English.

Uses English/ mathematical symbol.

Deals with arrays, variables, objects, arithmetic etc.HLL Progam must to translated into machine

language by using compiler or interpreter.

The first HLL designed in 1950sEx. C, C++, Basic, Cobol, Pascal Fortran.JAVA, JAVA Script.VB, VB .NET

Scripting Language

These lang. can be executed without explicit compilation and linking.

Scripting lang. are interpreted rather than complied.These are used in Web Development for

validation control etc.E.g. Java Script, VB Script, ASP, JSP, PHP, Perl, Ruby, Shell, Phyton.

Advantages

It is easier to write code.Editing & running scripting code is fast.

Limitation :

SlowerHarder to debug as no development environment is available by default.All scripting lang. are not supported by all the systems.

Natural Languages

Natural lang. is the lang. which acquired naturally.

This is typically used for human communication

No training is required for these lang.

E.g English, French, Chinese etc.

Characteristics of Good Programming

Language

Simple & readable

Portable : Language should be machine independent

General: Programming language should allow writing

wide variety of programs so that the programmer can

become expert in many languages.

Widely Available

Efficient

Abstract

Selecting Programming Language

The targeted platform where the programming Will

run

The elasticity of a lang. in which new features can be

added to the existing programming

The performance

Community support.

Environment: Platform, Web, Network Scientific,

General etc.

Subprogram (function)

Suppose we want to add two nos. then we have to write

programming For it., Again suppose we want to

perform the subtraction then again we need to write the

same code. So it will increase the programming Size.

To avoid this we can write subroutine(subprogram)

which is a part of main program.

These are nothing but the set of instructions to do the

specific task send result back to main program.

Some HLL language

FORTRAN : FORmula TRANslation. Developed by IBM

in 1957. It is a SCIENTIC LANGUAGE. The versions are

FORTRAN 66,77.

COBOL : Common Business Oriented Language. It is

developed by a group of computer professionals called

Conference on Data Systems Language ( CODASYL) in

1959. Its primary domain is business, finance and admin.

BASIC: Beginners All Purpose Symbolic Instruction Code.

It is a first HLL which used on the personal computers.

SNOBOL: StriNg Oriented and SymBOlic Language

Developed in 1962 in Bell Labs

C++, Java, C# : Object Oriented Languages

Lisp

Lisp: Means List Processing Language

This is second oldest HLL than ForTran

Lisp was originally created as a

Practical mathematical notation for computer

programs

In 1956 John McCarthy first developed the basics

behind lisp.

In 1965 the primary dialect of LISP was created.

In 1980 OOPS concepts are added.

List of Interpreter are : Emacs, Omega, LispWorks

MatLab

It stands for Mathematics Laboratory.

This is not Open Source.

This is developed by MathWork

Company.

This lang. is basically used for Research

Purpose.

It has different tool box like Image

Processing, Wireless Network, Neural

Network.

Octave (Gnu Octave)

This open source.

This is equivalent to MATLAB.

All commands which work in MatLab can work in Octave.

GNU Octave is a high-level interpreted language, primarily

intended for numerical computations. It provides capabilities for

the numerical solution of linear and nonlinear problems, and for

performing other numerical experiments. It also provides

extensive graphics capabilities for data visualization and

manipulation. Octave is normally used through its interactive

command line interface, but it can also be used to write non-

interactive programs. The Octave language is quite similar to

Matlab so that most programs are easily portable.

What is ‘C’ ?

C is programming language developed at

AT&T’s Bell Laboratory of USA in

1972.

It was written by Dennis Ritchie.

C is popular because it is reliable, simple

and easy to use. In Industry so many new

languages coming and out in years but is

till popular since 4-5 decades.

Features of C

Currently, the most commonly-used language

for embedded systems

“High-level assembly”

Very portable: compilers exist for virtually

every processor

Easy-to-understand compilation

Produces efficient code

Features of C

C is the most popular programming language, C has many

advantages:

Modularity:

modularity is one of the important characteristics of C. We

can split the C program into no. of modules instead of

repeating the same logic statements (sequentially). It

allows reusability of modules.

Middle level language:

as a middle level language C combines both the

advantages of low level and high level languages. (arrays,

pointers etc).

General purpose programming language:

C can be used to implement any kind of applications

such as math’s oriented, graphics, business oriented

applications.

Portability: we can compile or execute C program

in any operating

system(unix, dos, windows).

Powerful programming language: C is very

efficient and powerful

programming language, it is best used for data

structures and designing system software.

Basic Concepts of C Programming

Language

There are 3 types of Computer wares.

1. Human ware:

The person, who can use the system, is called 'Human

Ware ". He is also called as "User".

2. Hardware :

The physical components (devices) of a system are

called "Hardware".

Eg. Monitor, CPU, Keyboard, Mouse etc.

3. Software :

Def: Set of related programs is called “Software".

Translators

Assembler:

It is translating software. It translates assembly code to binary and vice versa.

Compiler / Interpreter:

Both are translating soft wares. Those can translate high level language to binary language and vice versa.

Compiler can process a whole file at a time and it provides .exe files. But, Interpreter can process a file line-by-line only. It does not provide .exe files. This is the main difference between them.

Learning Steps in 'C' :

1. Character Set

2. Word

3. Instruction

4. Program

5. Software

Character Set :

Def: All allowable symbols in this language are

called "Character set". The following characters

are used in this language.

Lower case letters : a b c … z

Upper case letters : A B C….Z

Digits : 0 1 2 3…9

Other characters : + - * ( ) & % $ # { } [ ]’ “ : ; etc.

White space characters : blank, new line, tab space

etc.

Word:

Def: Group of characters is called a 'Word'.

There are 3 types of words in C.

1. Keyword 2. Variables and / or Identifiers 3. Constants

Instructions:

Def: Collection of words has returns a complete meaning and ends with a semicolon (;) is called an Instruction.

Types of Instructions

1. Type declaration Instructions:

Any variable is used in a program that must be declaring

its data type before using it.

syn:

datatype var1, var2 , ...;

Eg.

int a;

float data;

Char grade;

Types of Instructions

2. I/O Instructions:

To read data from key board (std. input device) using a

statement. That is called "Input instruction".

To display the information on the monitor (std. output

device) using a statement. That is called "Output

Instruction".

Syn:

scanf ( ) ; : This is the standard input instruction in C.

printf ( ) ; : This is the standard output Instruction in C.

3. Arithmetic instructions:

Def: These instructions can perform Arithmetic

calculations.

Eg.

c = a+b;

gross = basic + hra +da; etc.

4. Control instructions:

Def: To control the flow of execution of the

program using certain statements are called

"Control Instructions ".

Eg.

if statement, looping statements etc.

#include <stdio.h> void main(){

printf("Hello, World! \n");

}

Preprocessor directive

Main function of program

Function used for

printing out data on

screen

Escape Sequences Character

\b Backspace

\f Form feed

\n Newline

\r Return

\t Horizontal tab

\v Vertical tab

\\ Backslash

\‘ Single quotation mark

\“ Double quotation mark

\? Question mark

\0 Null character

Keywords in C

Identifiers

identify a variable, function, or any other user-

defined item.

An identifier starts with a letter

A to Z,

a to z, or

An underscore '_' followed by zero or more letters,

underscores,

Digits (0 to 9)

C does not allow punctuation characters such

as @, $, and % within identifiers.

C is a case-sensitive programming language.

mohd

a23b9

Here are some examples of acceptable identifiers −

mohd

zara

abc

move_name

a_123

myname50 _temp

j

a23b9

retVal

mohd

a23b9

C - Data Types

Data types in c refer to an extensive system

used for declaring variables or functions ofdifferent types.

C Data Types

C - Data Types

Type Format Spacifier Storage size Value range

char %c 1 byte -128 to 127 or 0 to 255

int %d 2 bytes -32,768 to 32,767

unsigned int %d 2 bytes 0 to 65,535

short %d 2 bytes -32,768 to 32,767

unsigned

short%d 2 bytes 0 to 65,535

long %ld 4 bytes -2,147,483,648 to 2,147,483,647

float %f 4 byte 1.2E-38 to 3.4E+38

double %lf 8 byte 2.3E-308 to 1.7E+308

long double %Lf 10 byte 3.4E-4932 to 1.1E+4932

C program for addition of two numbers

#include <stdio.h>

void main()

{

int a,b,c;

C=a+b;

printf(“Addition is : %d \n", c);

}

Get the size of int type on any machine

#include <stdio.h>

int main()

{

printf("Storage size for int : %d \n", sizeof(int));

return 0;

}

C - Variables

A variable is nothing but a name given to a storage area that

our programs can manipulate. the following basic variable

types

Type Description

charTypically a single octet(one byte). This is an integer

type.

int The most natural size of integer for the machine.

float A single-precision floating point value.

double A double-precision floating point value.

void Represents the absence of type.

Syntax:

type variable_list;int i, j, k;

char c, ch;

float f, salary;

double d;

C - Variables

In C programming, variables or memory

locations should be declared before it can be

used.

Similarly, a function also needs to be declared

before use.

Data types simply refers to the type and size

of data associated with variables and

functions.

Defining Constants

There are two simple ways in C to define

constants −

Using #define pre-processor

Syntax:

#define Identifier = Value;

Using const keyword

const Data type Identifier = Value;

Defining Constants

#include <stdio.h>

#define LENGTH 10

#define WIDTH 5

#define NEWLINE '\n'

int main()

{

int area;

area = LENGTH * WIDTH;

printf("value of area : %d", area);

printf("%c", NEWLINE);

return 0;

}

Defining Constants

#include <stdio.h>

int main()

{

const int LENGTH = 10;

const int WIDTH = 5;

const char NEWLINE = '\n';

int area;

area = LENGTH * WIDTH;

printf("value of area : %d", area);

printf("%c", NEWLINE);

return 0;

}

Variables

Local variables:

•Existence is only to the main program or

functions are called local variables.

•Local variables are declared with in the main

program or a function.

Global variables:

•Existence is to the both main() as well as other

functions are called global variables.

•Global variables are declared outside the

main() and other functions.

OperatorsAn operator is a symbol that tells the compiler to perform

specific mathematical or logical operation.

Operators are classified into 3 categories.

1. Unary Operators: Single operand with an operator is

called “Unary Operators”.

Unary Operation

Increment and Decrement operators.

Casting Operating.

Address of Operator

Value of Operator

Scope Resolution Operator.

Size of Operator

Operators2. Binary Operators: Two operands with an operator are

called “Binary Operators”.

Arithmetic Operator.

Logical Operator.

Bitwise Operator.

Relational Operator.

Arithmetic Operators

Operator Description Example

+ Adds two operands. A + B = 30

− Subtracts second operand from the

first.

A − B = -10

* Multiplies both operands. A * B = 200

/ Divides numerator by de-numerator. B / A = 2

% Modulus Operator and remainder of

after an integer division.

B % A = 0

++ Increment operator increases the

integer value by one.

A++ = 11

-- Decrement operator decreases the

integer value by one.

A-- = 9

Bitwise Operators : are used to perform binary

arithmetic.

~ Not

& AND

| OR

^ Xor

<< Shift left

>> Shift Right

~= Not Assignment

&= And Assignment

^= Xor assignment

|= Or assignment

<<= Shift left assignment

>>= Shift Right assignment

Logical Operators :

Operator Description Example

&&Called Logical AND operator. If both the

operands are non-zero, then thecondition becomes true.

(A && B) is false.

||Called Logical OR Operator. If any of

the two operands is non-zero, then thecondition becomes true.

(A || B) is true.

!

Called Logical NOT Operator. It is used

to reverse the logical state of its

operand. If a condition is true, thenLogical NOT operator will make it false.

!(A && B) is true.

Relational : Used to perform comparison. Relational

operators always results in Boolean value either 1 TRUE or 0 FALSE. Following is the list

Operator Description Example

== Checks if the values of two operands are

equal or not.

(A == B) is not true.

!= Checks if the values of two operands are

equal or not.

(A != B) is true.

> Checks if the value of left operand is greater

than the value of right operand.

(A > B) is not true.

< Checks if the value of left operand is less

than the value of right operand

(A < B) is true.

>= Checks if the value of left operand is greater

than or equal to the value of right operand.

(A >= B) is not true.

<= Checks if the value of left operand is less

than or equal to the value of right operand.

If yes, then the condition becomes true.

(A <= B) is true.

Bitwise Operator

Bitwise operator works on bits and perform bit-by-bit operation.

p q p & q p | q p ^ q

AND OR Ex- OR

0 0 0 0 0

0 1 0 1 1

1 1 1 1 0

1 0 0 1 1

Operators

3. Ternary Operators: Three expressions with an operator

are called “Ternary operators”. Ex. Ternary operators.

Syntax:

Condition ? True Value : False Value

Ex.

g = (x < y)? x:y

Assignment Operators

Operator Description Example

= Simple assignment operator C = A + B will assign

the value of A + B to C

+= Add AND assignment operator. C += A is equivalent to

C = C + A

-= Subtract AND assignment operator. C -= A is equivalent to

C = C - A

*= Multiply AND assignment operator. C *= A is equivalent to

C = C * A

/= Divide AND assignment operator. C /= A is equivalent to

C = C / A

%= Modulus AND assignment operator. C %= A is equivalent

to C = C % A

Precedence of operators

Operator precedence determines the sequence of

operation priority in which an expression is evaluated.

Certain operators have higher precedence than

others.

for example, the multiplication operator has a higher

precedence than the addition operator.

For example,

x = 7 + 3 * 2; here, x is assigned 13, not 20 because

operator * has a higher precedence than +, so it first gets

multiplied with 3*2 and then adds into 7.

Hierarchy of Operation

Priority Operators Description

First * / %

Second + -

Third =

The Operations in Paranthesis has the highest

priority. Then Above same rules are applied

Associativity

Operator Category Associatively

Unary (++,--) R->L

Arithmetic(*,/,%) L->R

Arithmetic(+,-) L->R

Relational L->R

Equality L->R

Logical R->L

Assignment R->L

Precedence of operators

Type Conversion / Type Casting Type casting is a way to convert a variable from one data type to another data type. There are two types of type casting in c language.

Implicit conversionImplicit conversions do not required any operator forconverted. They are automatically performed when a value iscopied to a compatible type in program.Explicit conversionIn c language , Many conversions, specially those that imply adifferent interpretation of the value, require an explicitconversion.

Syntax: (Data_type) Identifier.Example: y = (int) x

Implicit Conversion#include <stdio.h>

void main()

{

int i = 17;

int sum;

char c = 'c'; /* ASCII value of c is 99 */

sum = i + c;

printf("Value of sum : %d\n", sum );

}

Output :-

Value of sum : 116

Explicit Conversion#include <stdio.h>

void main()

{

int i = 17;

float j = 38.34;

int sum;

sum = i + (int) j ;

printf("Value of sum : %d\n", sum );

}

Output :-

Value of sum : 50