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Full Discussion: Pointer confusion
Top Forums Programming Pointer confusion Post 302888643 by dragonpoint on Sunday 16th of February 2014 10:50:06 AM
Old 02-16-2014
Pointer confusion
Here are two programs that pass a pointer to a variable but behave differently. Shouldnt the i in second program be 0 after the function call?

Code:
#include<stdio.h>

void changeI(int *i)
{
 *i = 10;
}

int main(void)
{
 int i=5;
 printf("%d before\n", i);
 changeI(&i);
 printf("%d after\n", i);
 return 0;
}

Code:
chlsvnc01> ./temp
5 before
10 after

Code:
chlsvnc01> cat prttst3.c
#include<stdio.h>

void copy_array(int * destArray, int * srcArray, int *i)
{
 while(*i)
 {
  *destArray++ = *srcArray++;
  *i--;
 }
 printf("%d is after copy\n", *i);
 return ;
}

int main (void)
{
 int i=30;
 int s[30] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29};
 int d[30];

 printf("i before = %d\n",i);
 copy_array(d,s,&i);
 printf("i after = %d\n",i);

 for(i=0;i<30;i++)
  printf("%d\t",d[i]);
 printf("\n");
 return 0;
}

Code:
chlsvnc01> ./prttst3
i before = 30
0 is after copy
i after = 30
0       1       2       3       4       5       6       7       8       9       10      11      12      13      14      15      16      17      18      19      20      21      22      23      24      25      26      27      28      29

Last edited by bartus11; 02-16-2014 at 12:02 PM.. Reason: Please use [code][/code] tags.
 

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LEARN ABOUT CENTOS

locale::codes::langfam

Locale::Codes::LangFam(3)				User Contributed Perl Documentation				 Locale::Codes::LangFam(3)

NAME

       Locale::Codes::LangFam - standard codes for language extension identification

SYNOPSIS

	  use Locale::Codes::LangFam;

	  $lext = code2langfam('apa');		       # $lext gets 'Apache languages'
	  $code = langfam2code('Apache languages');    # $code gets 'apa'

	  @codes   = all_langfam_codes();
	  @names   = all_langfam_names();

DESCRIPTION

       The "Locale::Codes::LangFam" module provides access to standard codes used for identifying language families, such as those as defined in
       ISO 639-5.

       Most of the routines take an optional additional argument which specifies the code set to use. If not specified, the default ISO 639-5
       language family codes will be used.

SUPPORTED CODE SETS

       There are several different code sets you can use for identifying language families. A code set may be specified using either a name, or a
       constant that is automatically exported by this module.

       For example, the two are equivalent:

	  $lext = code2langfam('apa','alpha');
	  $lext = code2langfam('apa',LOCALE_LANGFAM_ALPHA);

       The codesets currently supported are:

       alpha
	   This is the set of three-letter (lowercase) codes from ISO 639-5 such as 'apa' for Apache languages.

	   This is the default code set.

ROUTINES

       code2langfam ( CODE [,CODESET] )
       langfam2code ( NAME [,CODESET] )
       langfam_code2code ( CODE ,CODESET ,CODESET2 )
       all_langfam_codes ( [CODESET] )
       all_langfam_names ( [CODESET] )
       Locale::Codes::LangFam::rename_langfam  ( CODE ,NEW_NAME [,CODESET] )
       Locale::Codes::LangFam::add_langfam  ( CODE ,NAME [,CODESET] )
       Locale::Codes::LangFam::delete_langfam  ( CODE [,CODESET] )
       Locale::Codes::LangFam::add_langfam_alias  ( NAME ,NEW_NAME )
       Locale::Codes::LangFam::delete_langfam_alias  ( NAME )
       Locale::Codes::LangFam::rename_langfam_code  ( CODE ,NEW_CODE [,CODESET] )
       Locale::Codes::LangFam::add_langfam_code_alias  ( CODE ,NEW_CODE [,CODESET] )
       Locale::Codes::LangFam::delete_langfam_code_alias  ( CODE [,CODESET] )
	   These routines are all documented in the Locale::Codes::API man page.

SEE ALSO

       Locale::Codes
	   The Locale-Codes distribution.

       Locale::Codes::API
	   The list of functions supported by this module.

       http://www.loc.gov/standards/iso639-5/id.php
	   ISO 639-5 .

AUTHOR

       See Locale::Codes for full author history.

       Currently maintained by Sullivan Beck (sbeck@cpan.org).

COPYRIGHT

	  Copyright (c) 2011-2013 Sullivan Beck

       This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

perl v5.16.3							    2013-02-27						 Locale::Codes::LangFam(3)
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