I wonder why arrays in the C programming language are pointers to the first element of the array, not the first element of the array itself?
View 14 RepliesI'm trying to figure out how to code for this specific type of instance - I want to use a hash and have the key be a reference to an array, and not use the key in the standard way of it being a scalar. Basically, I have a large output that I need to process line by line, and rather have access to it as an array than a big block in a scalar. For the big block hash as a scalar I would do -
Code:
foreach $CONTROLLER (<CONTROLLER_LIST>) {
$ALL_DISKS{$CONTROLLER} = `ssh -n <commands>`;
}
Now I know I could take the scalar and split it to another array after the fact like -
Code:
@TEMP_HOLD = split (/s+/,$ALL_DISKS{$CONTROLLER});
How would I code it that I would have access to the key information as an array and not a scalar? I know it needs to be a pointer and we're going to have -> in there somewhere, but not sure how to approach it. Some of the documentaiton I've been reading about referencing I've found a little confusing so far, and trying to figure out how to use them in context of what I'm working on.
Exist it a perl function to count how much each array element is into array?
View 14 Replies View RelatedI'm trying to create an array with variable including hyphenbut ksh refuses the first element
set -A allArgs
set +A allArgs ${allArgs[@]} -all
set +A allArgs ${allArgs[@]} -date
[code]...
it's been a while since I logged on here! I've been trying my hand at a little perl and have hit a brick wall.I'm using the Imagemagick module to manipulate some images. I can get the following to work without issue:
Code:
$teampath = "/var/www/team1";
$player=Image::Magick->new;
[code]...
I'm reading "OReilly Learning Perl 5th Edition", and there are such words:Code:You can use an array element like $fred[2] in every place? where you could use any other scalavariable like $fred.At the bottom of the page, it explains the ? like this:Code:The most notable exception is that the control variable of a foreach loop, which you?ll see later in this chapter, must be a simple scalar.Since Perl has the save-and-restore mechanism for the control variable, why an array element can't be used as the control variable
View 1 Replies View RelatedI'm trying to figure how to create an small array of 3x3 arrays such I can do
Code:
SUM1(i) = SUM1(i) + SUM2
where i goes from 1 to 8 and SUM2 is a 3x3 array.
I'm trying to compile a program and it gives me the following:
I checked cmath-util.h:46 and cmath-util.h:48:
I'm not a C person, and the author is unavailable so far.
Groovy is an object-oriented programming language for the Java platform. I do not have experience in Java, only perl and shell scripts. Recently I have been asked to maintain a software written in groovy (also to make enhancements). So can I learn groovy without knowing java language. or isit I have to learn java before venturing into groovy.
View 1 Replies View RelatedI am unable to find a description of alsa's programing language, this sort of stuff:
[Code]...
I need to know what, for example, 'ttable' means and what is its syntax. This seems to be a state secret.
Is there any framework available for network programming in c language just like POCO in c++.
View 1 Replies View RelatedI'm trying to make a very small script with greasemonkey to do some automatic things when a page loads. The first thing I need to do is to click on a link. I've done that. Then I need to select the 3rd element of a drop down list that appears a few moments (depending on the connection) after the link is pressed, without reloading the page (ajax or something like that). This I can't get to work, The select has no id or class, but I can get its xpath value. There is only one select on the page. I've tried both setTimeOut and the DOMNodeInserted event with no effect.
Code:
// ==UserScript==
// @name test
// @namespace "www.google.com"
// @include www.mywebpage.com
// ==/UserScript==
[Code]....
So I have been trying for 8 hours to try to get the index of an element from a list in a Makefile. The problem is that after I get the index using all the methods I have tried, the index cant be used in the "word" function:
for instance:
$(OUTPUT2) : INDEX = $(shell echo $(OUTPUT2) | sed -r -e "s/[ ]+/
/g" | grep -n $@ | sed 's/^([0-9]*):.*/1/')
will create a variable INDEX defined specifically for each member of OUTPUT2, so that each output knows its index. Unfortunately, when I pass this $(INDEX) into word, it doesn't work:
$(OUTPUT2) : $(word $(INDEX), $(INPUT1)) $(word $(INDEX), $(INPUT2))
echo $(INAME) $(TMPBASE) $@
and I get the error:
Makefile:16: *** non-numeric first argument to `word' function: 'num'. Stop.
I feel like if I could just convert a string to a Makefile acceptable number this would just work....
i'm practicing in very basic c programs using the gcc compiler.I found that when i create two variables let's say
Code:
int a,b and Code: a=15;
b=3;
a=b;
b--;
then a equals 2.I thought that this isn't normal in C isn't it?I haven't had the time to read the gcc documentation yet...so i think it has something to do with my compiler's default settings.I use the
Code: gcc filename.c -o filename command to compile
Are all variables defined like pointers?
So the place where I'm having a problem is here:
Code:
typedef struct {
void **Mem_Chunk;
[code]...
What is the difference between *ptr++ and (*ptr)++. In my opinion the terminology is all over the place so if you could give an example it would be better.
View 8 Replies View Relatedi'm a bit stuck playing with the following class setup for glut. The actual issue is with the function pointers.Basically the following code is the opengl redbook cube example slightly modified.
View 2 Replies View RelatedI need to call functions that match an input string (if input str = "func1", call func1), so I have this:
Code:
#include <stdio.h>
#include <string.h>
void function_a(void) { printf("Function A
"); }
[Code].....
In the above example, the functions take no input arguments. Can they take a different number of arguments, for example, function_a(int), function_c(int, int), function_e(int, char, int)? How can I do that?
I want to know is there some more efficient way of passing a pointer to a local variable as a parameter to a function in x86 asm? Right now I have to move the base pointer to a temp register, subtract from the register and pass that, like this (assuming a local var at esp-4):
Code:
mov eax, ebp
sub eax, 4
push eax
Is there a better way?
I've seen all three uses:
type * pointer
type *pointer
type* pointer
Are these 3 forms essentially the same, i.e., is the spacing as used here a non-factor when declaring pointers?
I am trying to find a way to pull Node Pointers out of the model, for use in other areas of the program. The solution is probably simple but I haven't had any luck finding it.
Model for a QTreeView:
Code:
class testModel : public QAbstractItemModel
{
public:
testModel();
~testModel();
[code]....
I have the most strange problem ever in programming. I fork a process into a parent and a child. In every forked process i declare a pointer, malloc and define a different value for every pointer.When i printf the value and the address guess what? They both have the SAME ADDRESS but DIFFERENT values, as assigned..Here's the portion of my code:
pid = fork ();
switch (pid)
{
[code]....
tell me some sites for learning programing language Because i feel confusing for learning C programing language now I got so many questions by my studing and i want to solve them by myself too.
View 14 Replies View RelatedI changed my post because I found that solution, and didn't want to bother for that. But, since I didnt find a way to delete the post, I thought of updating it: I am beginning to write the code for the philosophers problem. As you know, they can eat, think or wait for forks. When they have 2 forks, one by each side, they eat. Then they set the 2 forks as available, and think.
Each philosopher is a thread. My problem is that it gives segmentation fault, somehow, when I try to initialize. The thing I really don't understand, is why it sometimes gives segmentation fault on initialization #0!!! (But generally on initialization #1) I have set 5 initializations in total, defined by N, that is also the number of threads I'm working on.
PHP Code: #include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<pthread.h>
#include<errno.h>
#include <time.h>
#define N 5
[Code]....
I have a problem on a program,the problem take a very long time when i try to add two big arrays element by elementI know that matlab make adding vectors more faster than adding element by element but I don't know how!!!do any body knew how matlab make vectors operations more faster than element by element???I want to make my calculation more faster because the program is very big
View 8 Replies View RelatedI was reading Kernighan Ritchie book chapter 4 which deals with character pointers.I am not able to understand following different type of declarations
Code:
char aname[][15] = { "Illegal month", "Jan", "Feb", "Mar" };
char amessage[] = "now is the time";
[code]...
need to process files within multiple directories and transfer these to a remote server. What I had in mind was to use arrays for this; code pasted below (explains it better):
Code:
#set the arrays
array_A=( fileA* pathtodestA hostA passwordA )
[code]...
I following structure
typedef struct
{
[code]...
Does diff not like arrays? How do achieve the following?
Code:
stuart@stuart:~/music transfer$ diff file1.txt file2.txt
1c1
< bonkers_in_phoenix.mp3
[code]....
I'm making script for automated compiling of one program which would output builds optimized for many architectures. For clearancy, I do each build in it's own catalogue and list of builds with their respective catalogues would be stored as array. I'm using this guide as reference. It describes making array as naming a variable with additional brackets denoting it's position in array.
In my code, it looks exactly like this:
Code:
mtune[1]="build/mtune/athlon"
mtune[2]="build/mtune/athlon-4"
mtune[3]="build/mtune/athlon-mp"
[code]....
But upon invoking $mtune or any $mtune[x] variable, output is blank, like the variable(s) were never initialized. What am I doing wrong?