Academic Tutorials



English | French | Portugese | German | Italian
Home Advertise Payments Recommended Websites Interview Questions FAQs
News Source Codes E-Books Downloads Jobs Web Hosting
Chats

C Tutorial
Introduction to C Programming
Variables in C
Opertaors in C
Branching Statement in C
Looping Statement in C
C Storage Class
Functions in C
The C Preprocessor
Input/Output Functions in C
File I/O Functions in C
Pointers in C
Arrays in C
Dynamic Memory Allocation in C
Strings in C
Structures in C

HTML Tutorials
HTML Tutorial
XHTML Tutorial
CSS Tutorial
TCP/IP Tutorial
CSS 1.0
CSS 2.0
HLML
XML Tutorials
XML Tutorial
XSL Tutorial
XSLT Tutorial
DTD Tutorial
Schema Tutorial
XForms Tutorial
XSL-FO Tutorial
XML DOM Tutorial
XLink Tutorial
XQuery Tutorial
XPath Tutorial
XPointer Tutorial
RDF Tutorial
SOAP Tutorial
WSDL Tutorial
RSS Tutorial
WAP Tutorial
Web Services Tutorial
Browser Scripting
JavaScript Tutorial
VBScript Tutorial
DHTML Tutorial
HTML DOM Tutorial
WMLScript Tutorial
E4X Tutorial
Server Scripting
ASP Tutorial
PERL Tutorial
SQL Tutorial
ADO Tutorial
CVS
Python
Apple Script
PL/SQL Tutorial
SQL Server
PHP
.NET (dotnet)
Microsoft.Net
ASP.Net
.Net Mobile
C# : C Sharp
ADO.NET
VB.NET
VC++
Multimedia
SVG Tutorial
Flash Tutorial
Media Tutorial
SMIL Tutorial
Photoshop Tutorial
Gimp Tutorial
Matlab
Gnuplot Programming
GIF Animation Tutorial
Scientific Visualization Tutorial
Graphics
Web Building
Web Browsers
Web Hosting
W3C Tutorial
Web Building
Web Quality
Web Semantic
Web Careers
Weblogic Tutorial
SEO
Web Site Hosting
Domain Name
Java Tutorials
Java Tutorial
JSP Tutorial
Servlets Tutorial
Struts Tutorial
EJB Tutorial
JMS Tutorial
JMX Tutorial
Eclipse
J2ME
JBOSS
Programming Langauges
C Tutorial
C++ Tutorial
Visual Basic Tutorial
Data Structures Using C
Cobol
Assembly Language
Mainframe
Forth Programming
Lisp Programming
Pascal
Delphi
Fortran
OOPs
Data Warehousing
CGI Programming
Emacs Tutorial
Gnome
ILU
Soft Skills
Communication Skills
Time Management
Project Management
Team Work
Leadership Skills
Corporate Communication
Negotiation Skills
Database Tutorials
Oracle
MySQL
Operating System
BSD
Symbian
Unix
Internet
IP-Masquerading
IPC
MIDI
Software Testing
Testing
Firewalls
SAP Module
ERP
ABAP
Business Warehousing
SAP Basis
Material Management
Sales & Distribution
Human Resource
Netweaver
Customer Relationship Management
Production and Planning
Networking Programming
Corba Tutorial
Networking Tutorial
Microsoft Office
Microsoft Word
Microsoft Outlook
Microsoft PowerPoint
Microsoft Publisher
Microsoft Excel
Microsoft Front Page
Microsoft InfoPath
Microsoft Access
Accounting
Financial Accounting
Managerial Accounting
Network Sites


Dynamic Memory Allocation in C

Previoushome Next




What is Dynamic Memory Allocation?

  • Dynamic Memory Allocation is defined as the dynamically allocation of space for variables at runtime.


  • A D V E R T I S E M E N T
  • It is wasteful when dealing with array type structures to allocate so much space when it is declared



  • Five ANSI Standartd Function Used in Dynamic Memory Allocation

    ANSI C provides five standard functions that will help you allocate memory on the heap which are as follows:

    1. sizeof()
    2. malloc()
    3. calloc()
    4. realloc()
    5. free()




    The following table describe the five different standard functions that helps you allocate memory dynamically

    Function Task
    sizeof The sizeof() function returns the memory size of the requested variable
    malloc Allocates memory requests size of bytes and returns a pointer to the Ist byte of allocated space
    calloc Allocates space for an array of elements initializes them to zero and returns a pointer to the memory
    free Frees previously allocated space
    realloc Modifies the size of previously allocated space.



    sizeof()

    The sizeof() function returns the memory size of requested variable. This call should be used in the conjunction with the calloc() function call, so that only the necessary memory is allocated, rather than a fixed size. Consider the following,

    struct date {
    int hour, minute, second;
    };

    int x;

    x = sizeof( struct date );



    malloc()

    A block mf memory may be allocated using the function called malloc. The malloc function reserves a block of memory of specified size and return a pointer of type void. This means that we can assign it to any type of the pointer. It takes the following form:

    ptr=(cast-type*)malloc(byte-size);

    ptr is a pointer of type cast-type the malloc returns a pointer (of cast type) to an area of memory with the size byte-size. The following is the example of using malloc function

    x=(int*)malloc(100*sizeof(int));



    calloc()

    Calloc is another memory allocation function that is normally used to request the multiple blocks of storage each of same size and then sets all bytes to zero. The general form of calloc is:

    ptr=(cast-type*) calloc(n,elem-size);

    The above statement allocates contiguous space for n blocks each size of the elements size bytes. All bytes are initialized to zero and a pointer to the first byte of allocated region is returned. If there is not enough space a null pointer is also returned.




    realloc()

    The memory allocated by using calloc or malloc might be insufficient or excess sometimes in both the situations we can change the memory size already allocated with the help of the function called realloc. This process is called the reallocation of memory. The general statement of reallocation of memory is :

    ptr=realloc(ptr,newsize);



    free()

    Compile time storage of a variable is allocated and released by the system in accordance with its storage class. With the dynamic runtime allocation, it is our responsibility to release the space when it is not required at all.When the storage is limited,the release of storage space becomes important . When we no longer need the data we stored in a block of memory and we do not intend to use that block for the storing any other information, Using the free function,we may release that block of memory for future use.

    free(ptr);

    ptr is a pointer that has been created by using calloc or malloc.




    The following program illustrate the reallocation of memory using realloc() and malloc()



    View comments on this page.

    Posted By ranjeet kumar on: Saturday, October 2, 2010
    examples
    where is the programe using link list?




      C Tutorial eBooks
    More Links » »
     
     C Tutorial FAQs
    More Links » »
     
     C Tutorial Interview Questions
    More Links » »
     
     C Tutorial Articles
    More Links » »
     
     C Tutorial News
    More Links » »
     
     C Tutorial Jobs
    More Links » »

    Share And Enjoy:These icons link to social bookmarking sites where readers can share and discover new web pages.
    • blinkbits
    • BlinkList
    • blogmarks
    • co.mments
    • connotea
    • del.icio.us
    • De.lirio.us
    • digg
    • Fark
    • feedmelinks
    • Furl
    • LinkaGoGo
    • Ma.gnolia
    • NewsVine
    • Netvouz
    • RawSugar
    • Reddit
    • scuttle
    • Shadows
    • Simpy
    • Smarking
    • Spurl
    • TailRank
    • Wists
    • YahooMyWeb

    Previoushome Next

    Keywords: Dynamic Memory Allocation in C, dynamic memory allocation in c++, c arrays, c tutorial, c array, void c, c syntax, unix memory, value allocation, c language, return c, memory type, dynamic example, dynamic algorithm, dynamic tutorial, c example, c algorithm, variable c, c type, c program, memory size, unix c

    HTML Quizzes
    HTML Quiz
    XHTML Quiz
    CSS Quiz
    TCP/IP Quiz
    CSS 1.0 Quiz
    CSS 2.0 Quiz
    HLML Quiz
    XML Quizzes
    XML Quiz
    XSL Quiz
    XSLT Quiz
    DTD Quiz
    Schema Quiz
    XForms Quiz
    XSL-FO Quiz
    XML DOM Quiz
    XLink Quiz
    XQuery Quiz
    XPath Quiz
    XPointer Quiz
    RDF Quiz
    SOAP Quiz
    WSDL Quiz
    RSS Quiz
    WAP Quiz
    Web Services Quiz
    Browser Scripting Quizzes
    JavaScript Quiz
    VBScript Quiz
    DHTML Quiz
    HTML DOM Quiz
    WMLScript Quiz
    E4X Quiz
    Server Scripting Quizzes
    ASP Quiz
    PERL Quiz
    SQL Quiz
    ADO Quiz
    CVS Quiz
    Python Quiz
    Apple Script Quiz
    PL/SQL Quiz
    SQL Server Quiz
    PHP Quiz
    .NET (dotnet) Quizzes
    Microsoft.Net Quiz
    ASP.Net Quiz
    .Net Mobile Quiz
    C# : C Sharp Quiz
    ADO.NET Quiz
    VB.NET Quiz
    VC++ Quiz
    Multimedia Quizzes
    SVG Quiz
    Flash Quiz
    Media Quiz
    SMIL Quiz
    Photoshop Quiz
    Gimp Quiz
    Matlab Quiz
    Gnuplot Programming Quiz
    GIF Animation Quiz
    Scientific Visualization Quiz
    Graphics Quiz
    Web Building Quizzes
    Web Browsers Quiz
    Web Hosting Quiz
    W3C Quiz
    Web Building Quiz
    Web Quality Quiz
    Web Semantic Quiz
    Web Careers Quiz
    Weblogic Quiz
    SEO Quiz
    Web Site Hosting Quiz
    Domain Name Quiz
    Java Quizzes
    Java Quiz
    JSP Quiz
    Servlets Quiz
    Struts Quiz
    EJB Quiz
    JMS Quiz
    JMX Quiz
    Eclipse Quiz
    J2ME Quiz
    JBOSS Quiz
    Programming Langauges Quizzes
    C Quiz
    C++ Quiz
    Visual Basic Quiz
    Data Structures Using C Quiz
    Cobol Quiz
    Assembly Language Quiz
    Mainframe Quiz
    Forth Programming Quiz
    Lisp Programming Quiz
    Pascal Quiz
    Delphi Quiz
    Fortran Quiz
    OOPs Quiz
    Data Warehousing Quiz
    CGI Programming Quiz
    Emacs Quiz
    Gnome Quiz
    ILU Quiz
    Soft Skills Quizzes
    Communication Skills Quiz
    Time Management Quiz
    Project Management Quiz
    Team Work Quiz
    Leadership Skills Quiz
    Corporate Communication Quiz
    Negotiation Skills Quiz
    Database Quizzes
    Oracle Quiz
    MySQL Quiz
    Operating System Quizzes
    BSD Quiz
    Symbian Quiz
    Unix Quiz
    Internet Quiz
    IP-Masquerading Quiz
    IPC Quiz
    MIDI Quiz
    Software Testing Quizzes
    Testing Quiz
    Firewalls Quiz
    SAP Module Quizzes
    ERP Quiz
    ABAP Quiz
    Business Warehousing Quiz
    SAP Basis Quiz
    Material Management Quiz
    Sales & Distribution Quiz
    Human Resource Quiz
    Netweaver Quiz
    Customer Relationship Management Quiz
    Production and Planning Quiz
    Networking Programming Quizzes
    Corba Quiz
    Networking Quiz
    Microsoft Office Quizzes
    Microsoft Word Quiz
    Microsoft Outlook Quiz
    Microsoft PowerPoint Quiz
    Microsoft Publisher Quiz
    Microsoft Excel Quiz
    Microsoft Front Page Quiz
    Microsoft InfoPath Quiz
    Microsoft Access Quiz
    Accounting Quizzes
    Financial Accounting Quiz
    Managerial Accounting Quiz
    Testimonials | Contact Us | Link to Us | Site Map
    Copyright ? 2008. Academic Tutorials.com. All rights reserved Privacy Policies | About Us
    Our Portals : Academic Tutorials | Best eBooksworld | Beyond Stats | City Details | Interview Questions | Discussions World | Excellent Mobiles | Free Bangalore | Give Me The Code | Gog Logo | Indian Free Ads | Jobs Assist | New Interview Questions | One Stop FAQs | One Stop GATE | One Stop GRE | One Stop IAS | One Stop MBA | One Stop SAP | One Stop Testing | Webhosting in India | Dedicated Server in India | Sirf Dosti | Source Codes World | Tasty Food | Tech Archive | Testing Interview Questions | Tests World | The Galz | Top Masala | Vyom | Vyom eBooks | Vyom International | Vyom Links | Vyoms | Vyom World | Important Websites
    Copyright ? 2003-2021 Vyom Technosoft Pvt. Ltd., All Rights Reserved.