Learn Programming

An Introduction to .NET Framework

 The .NET Framework is a Microsoft's development platform.
 It offers to develop software applications.
 It was released by Microsoft Corporation in 2002. Later on several improvements take place in .NET Framework, which makes it as much strong, advanced and more efficient platform for building different kinds of software applications.
 Why it is called as “platform” is, it acts as platform for multiple languages, tools and libraries.
 It offers visually stunning user experiences, which is mostly required today’s competitive programming world.
 It offers much advanced security features never before.
 Supports dozens of languages like C#, VB.NET, VC++.NET, COBOL, Pascal, Python etc.

Features of .NET Framework

 Next Generation User Experiences:

.NET offers a Framework for building applications and high-fidelity experiences in Windows that blend together application UI, documents, and media content, while exploiting the full power of the computer. WPF (Windows Presentation Foundation) offers developers support for 2D and 3D graphics, hardware accelerated effects, scalability to different form factors, interactive data visualization, and superior content readability.

 Seamless and Secured Environment:

Application security is a big deal these days; perhaps the most closely examined feature of any new application. .NET offers its best secured environment at run time. So that it is highly impossible to access the .NET application and its related data by the un-authorized users / hackers.
The assembly (the compiled code of .NET framework) contains the security information like which categories of users or who can access the class or method. So that we can say that .NET Framework applications are much secured.
The security can be improved in the ASP.NET Web Sites by Security models like Integrated Windows Authentication, Microsoft Passport Authentication, Forms Authentication, and Client Certificate authentication.

 Multi Language Support:

.NET provides a multi-language development platform, so you can work in the programming language you prefer. The Common Language Runtime (A part of .NET Framework) provides support for 3 Microsoft developed languages and several other languages from other vendors.
Languages Supported by .NET Framework

Languages from Microsoft

Visual C#.NET
Visual Basic.NET
Visual C++.NET
Languages from other vendors

APL,
Cobol,
Perl,
Pascal,
Component Pascal,
Curriculum,
Eiffel,
Forth,
Fortran,
Haskell,
J#,
Mercury,
Mondrian,
Oberon,
Python,
IronPython,
RPG,
Scheme,
Small Talk,
Standard ML

 Flexible Data Access:
.NET Framework supports flexible accessibility of database data with ADO.NET (ActiveX Data Objects .NET). ADO.NET is a set of classes that expose data access services to the .NET programmer. ADO.NET provides a rich set of components for creating distributed, data-sharing applications. It is an integral part of the .NET Framework, providing access to relational, XML, and application data.

Modules of .NET

1. C#.NET (C Sharp.NET) –(Language)
 It is highly used .NET programming language, used by most of the .NET programmers.
 It borrows some programming features from “C” and some other programming features from “C++”. In addition to these, it borrows few of the good features of java language.
 It is the object oriented programming language.
2. VB.NET (Visual Basic.NET) –(Language)
 It is the Microsoft’s recommended language for beginners of windows programming.
 But in fact, it is used in very few of the projects in the real-time development world, because most of the programmers usually comes with “C” and “C++” background; hence they feel comfortable with “C#”.
 It borrows some programming features from VB (Visual Basic) language.
 It is the object oriented programming language.
3. ASP.NET (Active Server Pages.NET) – (Web Technology)
 It is the Microsoft’s web technology.
 It is used for web sites development.
 It offers much attractive and user friendly user interfaces in the server side applications.
 It is the new version to another Microsoft’s technology called ASP (Active Server Pages), which is a famous web technology before introducing ASP.NET.
 It requires HTML for web page designing.
 It requires a .NET language (like C#, VB.NET, VC++.NET etc.) for server side logic implementation.
4. ADO.NET (ActiveX Data Objects.NET) – (Database Technology)
It is the Microsoft’s database technology.
 It offers necessary programming libraries to access the local / server databases.
 It is the new version to another Microsoft’s technology called ADO (ActiveX Data Objects), which is a famous database technology, used with VB, VC++ and ASP languages.
 It requires a .NET language (like C#, VB.NET, VC++.NET etc.) for logic implementation.

.NET FRAMEWORK in-depth

.NET Framework Types:

The .NET Framework is available in 4 different types:

 .NET Framework: This is the general version, required to run .NET applications on Windows operating system.

 .NET Compact Framework: This is required to run .NET applications on other devices like PDA (Personal Digital Assistants), Mobile phones and Smart phones.

 .NET Micro Framework: This is very much smaller in memory size. This is designed to run .NET applications on the like Mobile phones and Smart phones having small memory capacity.

 .NET Mono Framework: This is required to run .NET applications on other operating systems like UNIX, LINUX and Solaris etc.

Components of .NET Framework

The .NET Framework is simply a collection of two components.
1. FCL (.NET Framework Class Library)
2. CLR (Common Language Runtime)

.NET (vs) Java

Microsoft’s .NET and SUN’s Java are strong competitors.

Similarities

1.Both of these support to develop console applications, windows applications, web sites, web services etc.
2.Both use their own intermediate language. Java calls it as “byte code” and .NET calls it as “MSIL”.
3.Both are Object oriented programming languages.
4.Both support Remoting.
5.Both supports multi-threading.
6.Both are platform independent.
7.Both support web related languages like Java Script, XML, CSS etc.
8.Both support the recent web development technology like AJAX.
9.Both support “Garbage collection”, which automatically clears the un-used memory.
10.Both support to develop the applications for small devices like PDA’s, mobile phones, smart phones etc.
11.Both offer better security features in their own style.

Differences

.Net is cost effective. Costs more than $700 (nearly Rs. 35,000)
Java is open source product, which can be freely downloaded on the Internet.
.Net Supports Language Independency (supports multiple languages)
Java Doesn’t offers multiple languages
.Net Offers IDE as Visual Studio by Microsoft.
Java Doesn’t offer any IDE. But other IDE’s by other vendors such as Eclipse etc.
.Net Offers easiest and fastest application development, which indirectly reduces the cost of the software.
Java Requires much time for the application development, which indirectly increases the cost of the software.
.Net Designing the UI is very much easy with “Drag and Drop” technique.
In Java UI Design requires much programmer’s effort and stress.
In .Net AJAX is implementation is much easy.
In Java AJAX is implementation is much time taking process, requires much code to write.

Advantages of .NET

Supports multiple languages like VC#, VB.NET, VC++.NET, VJ#.NET etc., so that the programmer can write the code in his/her interested language.
 Offers more secured environment never before.
 Offers flexible data access with ADO.NET
 Supports to develop windows services and web services, which are necessary to handle in the live projects in the modern programming world.
 Supports to develop applications for small devices like PDA’s, smart phones, mobile phones etc.
 Offers “platform independency”, because it supports to run the .NET applications on other platforms like UNIX, LINUX and Solaris etc., with .NET Mono framework.
 Offers easier and faster UI design (with drag and drop technique), when compared with the languages like Java.
 Offers the best debugging tools in the industry, which makes the programmer to easily fix the bugs.
 Offers improved object oriented programming features like properties, sealed classes, inner classes, delegates, enumerations, collections, interfaces, generics etc.
 Offers to share and reuse the code among multiple applications very easily, with the concept of “Assemblies”.
 Offers to write queries in the programming code itself, using the newly added feature called “LINQ” (Language Integrated Query). This is newly added feature in .NET 3.5.
 Offers faster and easier Deployment features, to generate “Installer packages” for installing the .NET application on the client systems.
 Offers to create multiple threads and also to manage them for creating Multi-Threaded Applications.
 Offers XML support and interaction, which is mostly required in the modern application development environment.
 Supports to create user defined graphics like lines, rectangles, bars, circles etc., very easily using “GDI+” (Graphics Device Interface) concepts.
 Offers a new and attractive feature called WPF (Windows Presentation Foundation), which is built on DirectX and which enables the programmer to create 2-D and 3-D graphics, animation, games, audio and view players etc. This is newly added feature in .NET 3.5.
 Offers another prestigious feature called WCF (Windows Communication Foundation), which integrates the network programming related libraries of .NET like .NET Remoting, SOAP enabled web services and message queues etc., which helps the programmer to develop service and network oriented applications using .NET. This is newly added feature in .NET 3.5.
 Support for the most recent web technology called AJAX (Asynchronous JavaScript and XML) along with ASP.NET. As a result of AJAX, the developer can produce newer generation user experiences on the web. Ex: www.orkut.com.

.NET (vs) Java

Microsoft’s .NET and SUN’s Java are strong competitors.
Similarities
1.Both of these support to develop console applications, windows applications, web sites, web services etc.
2.Both use their own intermediate language. Java calls it as “byte code” and .NET calls it as “MSIL”.
3.Both are Object oriented programming languages.
4.Both support Remoting.
5.Both supports multi-threading.
6.Both are platform independent.
7.Both support web related languages like Java Script, XML, CSS etc.
8.Both support the recent web development technology like AJAX.
9.Both support “Garbage collection”, which automatically clears the un-used memory.
10.Both support to develop the applications for small devices like PDA’s, mobile phones, smart phones etc.
11.Both offer better security features in their own style.

Differences

.NET FRAMEWORK in-depth

.NET Framework Types:
The .NET Framework is available in 4 different types:
 .NET Framework: This is the general version, required to run .NET applications on Windows operating system.
 .NET Compact Framework: This is required to run .NET applications on other devices like PDA (Personal Digital Assistants), Mobile phones and Smart phones.
 .NET Micro Framework: This is very much smaller in memory size. This is designed to run .NET applications on the like Mobile phones and Smart phones having small memory capacity.
 .NET Mono Framework: This is required to run .NET applications on other operating systems like UNIX, LINUX and Solaris etc.

Components of .NET Framework

The .NET Framework is simply a collection of two components.
1. FCL (.NET Framework Class Library)
2. CLR (Common Language Runtime)

Features of C Language

Features of “C” Language

It is robust language because of rich set of binary in – function
It is efficient and fast because of its variant data-types and powerful operation.
It is highly Portable i.e., programs written in one computer can be run on another
It is well suited for structure program, thus allows the user to think about the problem in the terms of functional blocks.
Debugging, testing and maintenance is easy
ability to extend itself, we can continuously add our own functions to the program.

Complier : This reads the entire source program and converts it to the object code. It provides error not of one line, but errors of the entire program. It executes as a whole and it is fast
Interpreter : It reads only one line of a source program at a time and converts it into an object code. In case of errors/same will be indicated instantly. It executes line by line and it is slow. Linker is a function which links up the files that in present in the operating system, it also links the files for the hardware and makes the system ready for executing.
Preprocessor : This is a program, that processes the source program before it is passed on to the compiler. The program typed in the editor is the source code to the preprocessor, then it passed the source code to the compiler. It is not necessary to write program with preprocessor & activity
Preprocessor directories are always initialize at the beginning of the program. it begins with the symbol (#) hash. It place before the main() function
Eg: # include <station>
# define PI 3.14
Character Set : The characters that can be used to form words and expressions depends upon the computer to which the program is run
The Characters in C are
1. Letters A-X, a-z, both upper and lower
2. Digits 0-9
3. Special character, +,-,*,”,;,./,
4. which spaces newline, horizontal tab;,carriage return ,blank space

Binary Operators In C Language

If any operation perform on two operands is known as binary operators .These are classified into following types

Arithmetic
Assignment
Relational
Logical
Bitwise

Arithmetic Operators : If any operation perform on Arithmetic values is known as arithmetic operators .These are classified into following types

Operator	Example
+ (Addition)	a+b
- (Substruction)	a-b
* (Multiplication)	a*b
/ (Division)	a/b
% (Modular Division)	a%b

#include<stdio.h>
#include<conio.h>
void main()
{
clrscr();
int x,y,z;
printf("Enter x ,y values");
scanf("%d%d",&x,&y);
z=x+y;
printf("Addition is %d",z);
getch();
}

Assignment Operators : Assignment operators are used to assign the values to the variable or assign the variable to variable .These are classified into following types

Operator	Example	Same as
=	a=b	a=b
+=	a+=b	a=a+b
-=	a-=b	a=a-b
*=	a*=b	a=a*b
/=	a/=b	a=a/b
%=	a%=b	a=a%b

#include<stdio.h>
#include<conio.h>
void main()
{
clrscr();
int x,y;
printf("Enter x ,y values");
scanf("%d%d",&x,&y);
x=x+y;
printf("Addition is %d",x);
getch();
}

Relational Operators : Relational operators are used to check the relation between two variables .These are classified into following types

Operator	Example
==	a==b
>	a>b
<	a<b
>=	a>=b
<=	a<=b
!=	a!=b

#include<stdio.h>
#include<conio.h>
void main()
{
clrscr();
int x,y,z;
printf("Enter x ,y values");
scanf("%d%d",&x,&y);
z=x>y;
printf("The Relation of x>y is %d",z);
getch();
}

Nore :Relational operators are used in conditional statements only

Logical Operators : Logical operators are used to combine the morethan one condition .These are classified into following types

Operator	Example
Logical AND &&	a>b && a>c
Logical OR \|\|	a>b \|\| a>c
Logical NOT !	!(a>b && a>c)

#include<stdio.h>
#include<conio.h>
void main()
{
clrscr();
int x,y,z,p;
printf("Enter x , y, z values");
scanf("%d%d%d",&x,&y,&z);
p=(x>y && x>z);
printf("The Logical AND is %d",p);
getch();
}

Nore :Logical operators are used in conditional statements only

Bitwise Operators : Bitwise operators are used to perform any operation on binary values .These are classified into following types

Operator	Example
Bitwise AND &	a&b
Bitwise OR \|	a\|b
Bitwise CAP ^	a^b
Bitwise NAGETION ~	~a
Bitwise LEFT SHIFT <<	a<<b
Bitwise Right SHIFT >>	a>>b

#include<stdio.h>
#include<conio.h>
void main()
{
clrscr();
int x,y,z;
printf("Enter x , y values");
scanf("%d%d",&x,&y);
z=x&y;
printf("The Bitwise AND is %d",z);
getch();
}

Fundamentals of C Language

“C” Tokens

Individual words and punctuation marks are characters. In a “C” program the smallest individual units are known as “C” tokens. It has 6types of token‟s

Keywords
Identifiers
Constants
Variables
Data types
Type def

Keywords
Keyword is an predefined word ,Which is an already defined by the C-Develphers
Ex:int ,float,char,if etc...
C-Language contains 32 Keywords

Constants
Constant is an identifier whose value can't be changed.
Ex:int x=10;
Here 10 is a Constant
x is a Variable
int is a Datatype
These constants are classified into 2 types

Numerical Constants
Character Constants

Numerical Constants:

Integer Constants
Real Constants

Integer Constants:

Real Constants

Character Constants

Single character constants
String character constants

Single character Constants:

String character Constants

Variable

Variable
Variable is an identifier whose value can be changed or which holds the data
Ex:int x=12;
x=20;
Variable Declaration Rules:

Variable name must be start with alphabet or underscore or doller symbol

The max length of the variable name is upto 32 characcters
If variable name contains morethan one word ,The second word onwords first letter should be uppercase letter
No spaces are allowed at the middle of the variable declaration
If variable value contains constant value that variable name must be uppercase

If constant variablename contains morethan one word ,It should be separated with underscore
All keywords are lowercase letters
We should not take keyword as a variable name

Variable Defination Types

Initilization
Declaration
Assignment

Initilization:

It menas initilize the some value to the variable
Ex:int x=12; here 12 is initilize to the x

Declaration

In the Declaration no value initilize to the variable
Ex:int x;

Assignment

In the assignment assign the value to the variable or assign variable to the variable
Ex:int x;
     x=12;(value to variable)
     int y;
     y=x;(variable to variable)

Datatypes

Datatypes are used to identify the type of data or which allocates the sufficient memory space for the varables. These Datatypes are classified into following types:

Primitive Datatypes
Derived Datatypes
Userdefined Datatypes

Primitive Datatypes:

Primitive datatypes are used to store the single value at a time
Ex:int x=12;
int y=12,13;(invalid) These Primitive datatypes are classified into following types

Integer datatype
Floating point datatypes
Character datatypes
Void Datatypes

Derived Datatypes:

These are used to store the morethan one value similar type
Ex:Arrays--- int marks[]={12,12,12,12,12,12}

Userdefined Datatypes:

These are used to store the morethan one value dissimilar type
Ex:structure,union

Type def : Defined as type definition by using typedef we can create new datatype. Typedef type data _ame;
Type ---- datatype
Dataname---- Name of that type

Typedef In C Language

Creating a new datatype using existing datatype is known as typedef

typedef int BYTE;
Here Byte is new Datatype

#include <stdio.h>
#include <string.h>
#include <conio.h>
 
typedef struct Books {
   char title[150];
   char author[150];
   char subject[200];
   int book_id;
} Book;
 
int main( ) {

   Book book;
 
   strcpy( book.title, "Java Programming");
   strcpy( book.author, "Dennis Ritchie"); 
   strcpy( book.subject, "java Programming Tutorial");
   book.book_id = 1224;
 
   printf( "Book title : %s\n", book.title);
   printf( "Book author : %s\n", book.author);
   printf( "Book subject : %s\n", book.subject);
   printf( "Book book_id : %d\n", book.book_id);

   getch();
}

typedef vs #define #define is a C-directive which is also used to define the aliases names for various datatypes.
It is Similar to typedef but following differences.
typedef is limited to giving symbolic names to types only where as #define can be used to define alias for values as well, q., you can define 1 as ONE etc.
typedef interpretation is performed by the compiler whereas #define statements are processed by the pre-processor.

#include <conio.h>
#include <stdio.h>
 
#define TRUE  1
#define FALSE 0
 
void main( ) {
   printf( "Value of TRUE : %d\n", TRUE);
   printf( "Value of FALSE : %d\n", FALSE);

   getch();
}

Control Statements In C-Language

Control statements are used to random execution of the program .These are classified into following types

Conditional Statements
Looping Statements
Unconditional Statements

Conditional Statements

if Condition
if else Condition
else if Condition
nested if Condition
switch Expression

if Condition:

if(Condition)
{
------
------
}

2.if else Condition:

if else

if(Condition)
{
------
------
}
else
{
------
------
}

#include<stdio.h>
#include<conio.h>
void main()
{
clrscr();
int x;
printf("Enter x value");
scanf("%d",&x);
if(x%2==0)
{
printf("Even Number");
}
else
{
printf("Odd Number");
}
getch();
}

3.else if Condition:

else if

if(Condition)
{
------
------
}
else if(Condition)
{
------
------
}
else if(Condition)
{
------
------
}
else if(Condition)
{
------
------
}
.
.
.
.
else
{
------
------
}

#include<stdio.h>
#include<conio.h>
void main()
{
clrscr();
int age;
printf("Enter your age");
scanf("%d",&age);
if(age>0 && age<=12)
{
printf("You are Child");
}
else if(age>12 && age<=19)
{
printf("You are Teen");
}
else if(age>19 && age<=40)
{
printf("You are Younger");
}
else if(age>40 && age<=80)
{
printf("You are Old");
}
else if(age>80 && age<=`00)
{
printf("You are Too Old");
}
else
{
printf("Invalid age");
}
getch();
}

4.Nested if Condition:

if(Condition)
{
    if(Condition)
    {
    ......
    ......
    }
    else
    {
    ......
    ......
    }
}
else
{
------
------
}

#include<stdio.h>
#include<conio.h>
void main()
{
clrscr();
int x;
printf("Enter x value");
scanf("%d",&x);
if(x>0)
{
    if(x%2==0)
    {
    printf("Even Number");
    }
    else
    {
    printf("Odd Number");
    }
}
else
{
printf("Please Enter Positive values");
}
getch();
}

5.Switch Expression:

Syntax :

switch(choice)
{
case 1:
	Statements;
        break;
case 2:
	Statements;
        break;
case 3:
	Statements;
        break;
      .
      .
      .
      .
      .
default:
	Statements;
}

#include<stdio.h>
#include<conio.h>
void main()
{
clrscr();
int x,y;
printf("Enter x value");
scanf("%d",&x);
y=x%2;
switch(y)
{
case 0:
	printf("Even number");
    break;
case 1:
	printf("Odd Number");
    break;
defalut:
	printf("Invalid Choice");
}
getch();
}

Variable Arguments in C-Language

Variable Arguments

Variable length argument is a feature that allows a function to receive any number of arguments.
There are situations where we want a function to handle variable number of arguments according to requirement.

Sum of given numbers.
Minimum of given numbers. and many more.

Variable number of arguments are represented by three dotes (…)
Syntax:

    datatype functionname(datatype,...)
    {
    ...
    ...
    }
    
    void main()
    {
    functionname(v1,v2,v3);
    functionname(v1,v2,v3,v4,v5);
    }

/* C Variable Length Arguments - This program
 * demonstrates variable length arguments in C
 */

#include<stdio.h>
#include<stdarg.h>
#include<conio.h>

int avg(int num, ...)
{
	va_list valist;
	int sum = 0;
	int i;

	// initializing valist for num number of arguments
	va_start(valist, num);

	// now accessing all the arguments that is assigned to valist
	for(i=0; i<num; i++)
	{
		sum = sum + va_arg(valist, int);
	}

	// now cleaning the memory reserved for the valist
	va_end(valist);

	return sum/num;
}

void main()
{
	int num1=10, num2=20, num3=30;
	clrscr();

	printf("The average is %d", avg(3, num1, num2, num3));

	getch();
}

Output:
The average is 20

Files In C Language

File : File is a collection of data or information which is used to store the data permanently
Types of files:
1.Text Files
2.Document Files
3.Audio Files
4.Video Files
5.PDF Files ...

File Operations
1.Open or create a file
2.Write the data into the file
3.Read the data from the file
4.close a file
Open file

FILE *fopen( const char * filename, const char * mode );

Here, filename is a string literal, which you will use to name your file, and access mode can have one of the following values −

Sno	Mode	Description
1	r	Opens an existing text file for reading purpose.
2	w	Opens a text file for writing. If it does not exist, then a new file is created. Here your program will start writing content from the beginning of the file.
3	a	Opens a text file for writing in appending mode. If it does not exist, then a new file is created. Here your program will start appending content in the existing file content.
4	r+	Opens a text file for both reading and writing.
5	w+	Opens a text file for both reading and writing. It first truncates the file to zero length if it exists, otherwise creates a file if it does not exist.
6	a+	Opens a text file for both reading and writing. It creates the file if it does not exist. The reading will start from the beginning but writing can only be appended.

If you are going to handle binary files, then you will use following access modes instead of the above mentioned ones −

  "rb", "wb", "ab", "rb+", "r+b", "wb+", "w+b", "ab+", "a+b"

Closing File:

int fclose( FILE *fp );
Close a file using fclose( ) function

Writing a File:

fprintf(file,"Data")

fputs("Data",File)

Program:

#include <stdio.h>
#include <conio.h>
void main() {
   FILE *fp;
   fp = fopen("test.txt", "w+");
   fprintf(fp, "This is testing File\n");
   fputs("This is testing File\n", fp);
   fclose(fp);
   printf("Success");
   getch();
}

Reading a File

fscanf(File,"type of data",variable);

fgets(variable,size, FILE)

Program

#include <stdio.h>
#include <conio.h>

void main() {

   FILE *fp;
   char x[255];

   fp = fopen("test.txt", "r");
   fscanf(fp, "%s", x);
   printf("1 : %s\n", x );

   fgets(x, 255, (FILE*)fp);
   printf("2: %s\n", x );
   
   fclose(fp);
   printf("Success");
   getch();

}

Functions in C Language

C Functions

Function is a collection of statements used to perform specific operation.In C Language these function are classified into following types

predefined Function
UserDefined Function

PreDefined Functions

printf()
Scanf()
getch()
clrscr()
sizeof() ...ete

UserDefined Function

If any function designed by the programmer is known as user defined function
Syntax

  returntype functionname(list of paramers/no parameters);    //function Declaration
  returntype functionname(list of paramers/no parameters)      //function Body
  {
  ....
  ....
  ....
  ....
  }

in the above syntax first you declare the function.Ofter you declare the function body
These functions are classified into fallowing types

Parametarized Function
NoParametarized Function

Parametarized Function:

If any function signature contains list of parameters is known as Parametarized Function.
Syntax

  returntype functionname(datatype variable1,datatype variable2,....);    //function Declaration
  returntype functionname(datatype variable1,datatype variable2,....)      //function Body
  {
  ....
  ....
  ....
  ....
  }

NoParametarized Function:

If any function signature does not contains list of parameters is known as NoParametarized Function.
Syntax

  returntype functionname();    //function Declaration
  returntype functionname()     //function Body
  {
  ....
  ....
  ....
  ....
  }

Based on the return type these functions are classified into following types

No Returntype With NoParametarized Function
No Returntype With Parametarized Function
Returntype With NoParametarized Function
Returntype With Parametarized Function

No Returntype With NoParametarized Function

#include<stdio.h>
#include<conio.h>
void max();
void max()
{
int x,y;
printf("Enter x,y values");
scanf("%d%d",&x,&y);
if(x>y)
{
printf("x is max");
}
else
{
prinf("y is max");
}
};
void main()
{
clrscr();
max();
getch();
}

No Returntype With Parametarized Function

#include<stdio.h>
#include<conio.h>
void max(int x,int y);
void max(int x,int y)
{

if(x>y)
{
printf("x is max");
}
else
{
prinf("y is max");
}
};
void main()
{
clrscr();
int x,y;
printf("Enter x,y values");
scanf("%d%d",&x,&y);
max(x,y);
getch();
}

Returntype With NoParametarized Function

#include<stdio.h>
#include<conio.h>
int max();
int max()
{
int x,y;
printf("Enter x,y values");
scanf("%d%d",&x,&y);
if(x>y)
{
return x;
}
else
{
return y;
}
};
void main()
{
clrscr();
printf("%d",max());
getch();
}

Returntype With Parametarized Function

#include<stdio.h>
#include<conio.h>
int  max(int x,int y);
int  max(int x,int y)
{

if(x>y)
{
return x;
}
else
{
return y;
}
};
void main()
{
clrscr();
int x,y;
printf("Enter x,y values");
scanf("%d%d",&x,&y);
printf("%d",max(x,y));
getch();
}

Function Calling

Function Calling Syntax :
functionname(arguments,...);
Example: max(10,20)
Here Max is a functionname
10,20 are the arguments

C - Recursion

The C programming language supports recursion, i.e., a function to call itself. But while using recursion, programmers need to be careful to define an exit condition from the function, otherwise it will go into an infinite loop.
Syntax :

 void recursion() {
   recursion(); /* function calls itself */
}

int main() {
   recursion();
}

#include<stdio.h>
#include<conio.h>
int factorial(int i) {

   if(i <= 1) {
      return 1;
   }
   return i * factorial(i - 1);
}

void  main() {
   int i = 5;
   printf("Factorial of %d is %d//n", i, factorial(i));
   getch();
}

Memory Management in C-Language

Memory Management

Dynamic Memory Allocation in C

The process of allocating memory at runtime is known as dynamic memory allocation.
Library routines known as memory management functions are used for allocating and freeing memory during execution of a program.
These functions are defined in stdlib.h header file.

Function	Description
malloc()	allocates requested size of bytes and returns a void pointer pointing to the first byte of the allocated space
calloc()	allocates space for an array of elements, initialize them to zero and then returns a void pointer to the memory
Free	releases previously allocated memory
realloc	modify the size of previously allocated space

Memory Allocation Process

Global variables, static variables and program instructions get their memory in permanent storage area whereas local variables are stored in a memory area called Stack.
The memory space between these two region is known as Heap area. This region is used for dynamic memory allocation during execution of the program. The size of heap keep changing.

Allocating block of Memory

malloc() function is used for allocating block of memory at runtime.
This function reserves a block of memory of the given size and returns a pointer of type void.
This means that we can assign it to any type of pointer using typecasting.
If it fails to allocate enough space as specified, it returns a NULL pointer.

Syntax:

    void* malloc(byte-size)

calloc()

It is another memory allocation function that is used for allocating memory at runtime.
calloc function is normally used for allocating memory to derived data types such as arrays and structures.
If it fails to allocate enough space as specified, it returns a NULL pointer.

Syntax:

void *calloc(number of items, element-size)

realloc()

realloc() changes memory size that is already allocated dynamically to a variable.

Syntax:

    void* realloc(pointer, new-size)