7/27/2019 C Programming Storage Class

1/2

Home C Programming C++ Programming FollowFollow

C Programming

C Introduction

C Keywords and Identifier

C Variables and Constants

C Programming Data Types

C Programming input/Output

C Programming Operators

C Precedence and Associativity

C Introduction Examples

C Decisions And Loops

C Programming if...else

C Programming for Loops

C do...while Loops

C break and continue

C Programming switch...case

C Programming goto

C Decision & Loop Examples

C Programming Functions

C Functions Introduction

C User-defined Functions

C Function Types

C Programming recursion

C Storage Class

C Function Examples

C Programming Arrays

C Arrays Introduction

C Multi-dimensional Arrays

C Arrays & Functions

C Arrays Examples

C Programming Pointers

C Pointers Introduction

C Pointers And Arrays

C Pointers And Functions

C Dynamic Memory Allocation

C Pointer Examples

C Programming Strings

C Programming Strings

C String Functions

C String Examples

C Structure And Unions

C Structure Introduction

C Structures and Pointers

C Structure and Function

C Programming Unions

C Structure Examples

C Programming Files

C Files Input/OutputC Files Examples

More On C Programming

C Programming Enumeration

C Programming Preprocessors

C Library Functions

C Programming Examples

Follow Us

C Programming Storage Class

Every variable and function in C programming has two properties: type and storage class. Type refers to the data

type of variable whether it is character or integer or floating-point value etc.

There are 4 types of storage class:

1. automatic

2. external

3. static

4. register

Automatic storage class

Keyword for automatic variableauto

Variables declared inside the funct ion body are automatic by default. The se variable are also known as local variables

as they are local to the function and doesn't have meaning outside that function

Since, variable inside a function is automatic by default, keyword auto are rarely used.

External storage classExternal variable can be accessed by any function. They are also known as global variables. Variables declared outside

every function are external variables.

In case of large program, containing more than one file, if the global variable is declared in file 1 and that variable is

used in file 2 then, compiler will show error. To solve this problem, keyword extern is used in file 2 to indicate that,

the variable specified is global variable and declared in another file.

Example to demonstrate working of external variable

#include

voidCheck();

int a=5;

/* a is global variable because it is outside every function */

int main(){

a+=4;

Check();

return 0;

}

voidCheck(){

++a;

/* ----- Variable a is not declared in this function but, works in any

function as they are global variable ------- */

printf("a=%d\n",a);

}

Output

a=10

Register Storage Class

Keyword to declare register variableregister

Example of register variable

register int a;

Register variables are similar to automatic variable and exists inside that particular function only.

Search

Like 804

Python devs at SlideShare

www.slideshare.net

Love python? Work with SlideShare at New Delhi. Apply Now!

http://www.programiz.com/c-programming/library-functionhttp://www.programiz.com/c-programming/c-file-exampleshttp://www.programiz.com/c-programming/c-structure-exampleshttp://www.programiz.com/c-programming/c-structure-functionhttp://www.programiz.com/c-programming/c-structureshttp://www.programiz.com/c-programming/string-handling-functionshttp://www.programiz.com/c-programming/c-dynamic-memory-allocationhttp://www.programiz.com/c-programming/c-pointers-arrayshttp://www.programiz.com/c-programming/c-pointershttp://www.programiz.com/c-programming/c-arrays-exampleshttp://www.programiz.com/c-programming/c-arrays-functionshttp://www.programiz.com/c-programming/c-arrayshttp://www.programiz.com/c-programming/c-recursionhttp://www.programiz.com/c-programming/c-user-defined-functionshttp://www.programiz.com/c-programming/c-decision-making-loops-exampleshttp://www.programiz.com/c-programming/c-switch-case-statementhttp://www.programiz.com/c-programming/c-break-continue-statementhttp://www.programiz.com/c-programming/c-for-loophttp://www.programiz.com/c-programming/precedence-associativity-operatorshttp://www.programiz.com/c-programming/c-input-outputhttp://www.programiz.com/c-programming/c-variables-constantshttp://www.programiz.com/c-programming/c-keywords-identifierhttp://www.programiz.com/http://www.programiz.com/c-programminghttp://www.programiz.com/cpp-programminghttp://www.programiz.com/http://www.programiz.com/http://googleads.g.doubleclick.net/aclk?sa=l&ai=CtcnsYUzuUYmxGYjOigfe-4D4BLns5ZUC2e_epSDAjbcBEAEg_4rkIVD48qOg_v____8BYOXK5YO0DqAB18G47wPIAQGoAwHIA9MEqgSQAU_Qh_tamywdQGkNwGTzd-p579quKAaKmB7URA4vBbSSNowmyAPqkiEAu6Kc19v81qaYEP1y6MKjVfCyU_9UUngwCtz1SlNgn3V046qTBrhENPMOvUYR09vg60QcWi-H2ABaXa2Kz8mlPnBJjaE2E7q43uB0MEBvG4u7MiS6xsYi4clKQSzksUFkrfKSZQEoeYAHkb7HEA&num=1&sig=AOD64_3waxyz_TRX1NMyIpx09jSJyJz-MA&client=ca-pub-9007421361448641&adurl=http://www.slideshare.net/about/workatslideshare&nm=3https://twitter.com/intent/follow?original_referer=http%3A%2F%2Fwww.programiz.com%2Fc-programming%2Fc-storage-class&region=follow_link&screen_name=programiz&tw_p=followbutton&variant=2.0http://www.google.com/url?ct=abg&q=https://www.google.com/adsense/support/bin/request.py%3Fcontact%3Dabg_afc%26url%3Dhttp://www.programiz.com/c-programming/c-storage-class%26gl%3DIN%26hl%3Den%26client%3Dca-pub-9007421361448641%26ai0%3DCtcnsYUzuUYmxGYjOigfe-4D4BLns5ZUC2e_epSDAjbcBEAEg_4rkIVD48qOg_v____8BYOXK5YO0DqAB18G47wPIAQGoAwHIA9MEqgSQAU_Qh_tamywdQGkNwGTzd-p579quKAaKmB7URA4vBbSSNowmyAPqkiEAu6Kc19v81qaYEP1y6MKjVfCyU_9UUngwCtz1SlNgn3V046qTBrhENPMOvUYR09vg60QcWi-H2ABaXa2Kz8mlPnBJjaE2E7q43uB0MEBvG4u7MiS6xsYi4clKQSzksUFkrfKSZQEoeYAHkb7HEA&usg=AFQjCNF6jpWgo_ws9rZt31ATBcQh_Km45ghttp://googleads.g.doubleclick.net/aclk?sa=l&ai=CtcnsYUzuUYmxGYjOigfe-4D4BLns5ZUC2e_epSDAjbcBEAEg_4rkIVD48qOg_v____8BYOXK5YO0DqAB18G47wPIAQGoAwHIA9MEqgSQAU_Qh_tamywdQGkNwGTzd-p579quKAaKmB7URA4vBbSSNowmyAPqkiEAu6Kc19v81qaYEP1y6MKjVfCyU_9UUngwCtz1SlNgn3V046qTBrhENPMOvUYR09vg60QcWi-H2ABaXa2Kz8mlPnBJjaE2E7q43uB0MEBvG4u7MiS6xsYi4clKQSzksUFkrfKSZQEoeYAHkb7HEA&num=1&sig=AOD64_3waxyz_TRX1NMyIpx09jSJyJz-MA&client=ca-pub-9007421361448641&adurl=http://www.slideshare.net/about/workatslideshare&nm=3http://www.programiz.com/http://www.programiz.com/c-programming/exampleshttp://www.programiz.com/c-programming/library-functionhttp://www.programiz.com/c-programming/c-preprocessor-macroshttp://www.programiz.com/c-programming/c-enumerationhttp://www.programiz.com/c-programming/c-file-exampleshttp://www.programiz.com/c-programming/c-file-input-outputhttp://www.programiz.com/c-programming/c-structure-exampleshttp://www.programiz.com/c-programming/c-unionshttp://www.programiz.com/c-programming/c-structure-functionhttp://www.programiz.com/c-programming/c-structures-pointershttp://www.programiz.com/c-programming/c-structureshttp://www.programiz.com/c-programming/c-string-exampleshttp://www.programiz.com/c-programming/string-handling-functionshttp://www.programiz.com/c-programming/c-stringshttp://www.programiz.com/c-programming/c-pointer-exampleshttp://www.programiz.com/c-programming/c-dynamic-memory-allocationhttp://www.programiz.com/c-programming/c-pointer-functionshttp://www.programiz.com/c-programming/c-pointers-arrayshttp://www.programiz.com/c-programming/c-pointershttp://www.programiz.com/c-programming/c-arrays-exampleshttp://www.programiz.com/c-programming/c-arrays-functionshttp://www.programiz.com/c-programming/c-multi-dimensional-arrayshttp://www.programiz.com/c-programming/c-arrayshttp://www.programiz.com/c-programming/c-functions-exampleshttp://www.programiz.com/c-programming/c-storage-classhttp://www.programiz.com/c-programming/c-recursionhttp://www.programiz.com/c-programming/types-user-defined-functionshttp://www.programiz.com/c-programming/c-user-defined-functionshttp://www.programiz.com/c-programming/c-functionshttp://www.programiz.com/c-programming/c-decision-making-loops-exampleshttp://www.programiz.com/c-programming/c-goto-statementhttp://www.programiz.com/c-programming/c-switch-case-statementhttp://www.programiz.com/c-programming/c-break-continue-statementhttp://www.programiz.com/c-programming/c-do-while-loopshttp://www.programiz.com/c-programming/c-for-loophttp://www.programiz.com/c-programming/c-if-else-statementhttp://www.programiz.com/c-programming/c-introduction-exampleshttp://www.programiz.com/c-programming/precedence-associativity-operatorshttp://www.programiz.com/c-programming/c-operatorshttp://www.programiz.com/c-programming/c-input-outputhttp://www.programiz.com/c-programming/c-data-typeshttp://www.programiz.com/c-programming/c-variables-constantshttp://www.programiz.com/c-programming/c-keywords-identifierhttps://plus.google.com/111117167860655769030http://www.twitter.com/programizhttp://www.facebook.com/programizhttps://twitter.com/intent/follow?original_referer=http%3A%2F%2Fwww.programiz.com%2Fc-programming%2Fc-storage-class&region=follow_link&screen_name=programiz&tw_p=followbutton&variant=2.0http://www.programiz.com/cpp-programminghttp://www.programiz.com/c-programminghttp://www.programiz.com/

7/27/2019 C Programming Storage Class

2/2

Recursive Function Function Examples

If the compiler encounters register variable, it tries to store variable in microprocessor's register rather than memory.

Value stored in register are much faster than that of memory.

In case of larger program, variables that are used in loops and function parameters are declared register variables.

Since, there are limited number of register in processor and if it couldn't store the variable in register, it will

automatically store it in memory.

Static Storage ClassThe value of static variable persists until the end of the program. A variable can be declared static using keyword:

static. For example:

static int i;

Here, i is a static variable.

Example to demonstrate the static variable

#include

voidCheck();

int main(){

Check();

Check();

Check();

}

voidCheck(){

static int c=0;

printf("%d\t",c);

c+=5;

}

Output

0 5 10

During first function call, it will display 0. Then, during second function call, variable c will not be initialized to 0

again, as it is static variable. So, 5 is displayed in second function call and 10 in third call.

If variable c had been automatic variable, the output would have been:

0 0 0

FROM 1,500

Scanner

FROM 2,000

Core Processor

FROM 8,000

Acer Laptop

Rexel Filing Cabinets

www.rexelindustries.com

Quality Steel Filing cabinets & Office Filing cabinets made in UAE

Like 0

Copyright programiz.com, 2011-2013 | All rights reserved | Google+

googleplus stumbleupon

https://plus.google.com/116050874615553634748?rel=authorhttp://www.google.com/url?ct=abg&q=https://www.google.com/adsense/support/bin/request.py%3Fcontact%3Dabg_afc%26url%3Dhttp://www.programiz.com/c-programming/c-storage-class%26gl%3DIN%26hl%3Den%26client%3Dca-pub-9007421361448641%26ai0%3DCvQxoYkzuUc6uKKy7igez-ICoB-Ttp5gD3OLXzFjAjbcBEAEg_4rkIVCa0eGg-v____8BYOXK5YO0DsgBAakC4V3k_lZFkj6oAwHIA9MEqgSNAU_QLpLTn__-VY1Ddvzm5v0Zk_S0cRYpx6lRngg5eCPMNN2icWjm9WTazLDH2w8QaK-CqB5lGcXffn24d4durEQdF7SnqxVnSPK5f3HbGXKkkQNyO3g18tNYAqvtmzdD98wTxUUwH7-DiehLH48IeitIu1ytQUR0LCkMTZTNNQOtex8lawy3VF3AZVrTdoAHnK27Hg&usg=AFQjCNEFdCkDEkaVrfhDarL4J2rWfIjsOwhttp://googleads.g.doubleclick.net/aclk?sa=L&ai=CvQxoYkzuUc6uKKy7igez-ICoB-Ttp5gD3OLXzFjAjbcBEAEg_4rkIVCa0eGg-v____8BYOXK5YO0DsgBAakC4V3k_lZFkj6oAwHIA9MEqgSNAU_QLpLTn__-VY1Ddvzm5v0Zk_S0cRYpx6lRngg5eCPMNN2icWjm9WTazLDH2w8QaK-CqB5lGcXffn24d4durEQdF7SnqxVnSPK5f3HbGXKkkQNyO3g18tNYAqvtmzdD98wTxUUwH7-DiehLH48IeitIu1ytQUR0LCkMTZTNNQOtex8lawy3VF3AZVrTdoAHnK27Hg&num=1&sig=AOD64_3gOm8QDQueK6Ou3NzBmjjLCRmBQQ&client=ca-pub-9007421361448641&adurl=http://www.rexelindustries.com/UAE-Filing-Cabinets.htmlhttp://www.programiz.com/c-programming/c-functions-exampleshttp://www.programiz.com/c-programming/c-recursion