Do you know how to make your own wc utility or any tutorials which will help you make one. We have to make our own wc utility for school which:
-uses command line options
-reading text from file
-counting the number of characters, words and lines in the file,
-using fork() to create child processes
I just want to say I dont want anyone to do it for me just assist me on where i can get help.
The most useful example is probably the solution provided in "The C Programming Language" by K&R. There is also a ready solution here (done in C, with literate programming).
It is beyond me why you would use fork() to create child processes. What for?
Related
I need to drive a testbench with labview.
The test scenarios are written in a languages that can be automaticaly translated into labview diagrams.
Is this an API that allow to create "labview diagrams" from another software ? or with labview itself ?
I agree that LabVIEW scripting is one approach, but let me throw out another option.
If you are planning to do a one time migration from your test code to LabVIEW than scripting is great, but if you plan to regularly update your test code (because it's easier to use the "test" language than LabVIEW) than it could become quite painful to constantly perform the migration every time your test code has changed.
I've had great success with simply putting my state machine inside of a for loop and then reading in "commands" from a text file that was generated using my "test" language (see pic).
For example, to do an IV sweep my text file might say something like:
SourceV, 5
ReadI
Wait, 1
SourceV, 6
ReadI
This image is greatly simplified - I'm not using a state machine and I don't show how to use "parameters," but I can provide a more comprehensive example if needed. Again, I've had great success doing this with around 30 "commands" controlling multiple instruments and then I generated the text input using VBA or Python.
It's called LabVIEW scripting. You will need to enable an option in the VI Server page in the options dialog to see the relevant features.
A few things to note:
Scripting isn't complicated, but you do need to be aware of how LV code is built.
While scripting is public, it was initially created as an internal tool. There are still corners of it which are incomplete.
Scripting code can be tedious. If you can get away with it, try creating templates of code.
NI has something called CodeGen, which I believe are a series of functions which make some scripting easier, although I never really looked into it.
Basically I'm wondering if I can compile code that a user inputs in a mac app (I'm trying to make an OCaml text editor that compiles your code) using executables that are already available in the user's system, such as ocamlc etc. I don't have any code to show or anything because I'm still figuring out if/how I could build this mac app. Not really sure what other info I should include, so just ask. Thanks!
You can use either Sys.command "<your shell command>" or Unix.open_process* and Unix.create_process commands. See man Sys and man Unix for more information.
In Objective-C, C, and C++, and a multitude of other languages, use system(3). Also see:
exec(3)
popen(3)
If you are using Objective-C, check out NSTask.
If not, look at popen. popen gives your parent process control over the I/O streams.
starting to work as an IT man lately
with some programing background,
there are so many occasions where there's a need for processing large amount of data.
mainly strings i guess..
for example:
there's 2 large sets of lines, and we need all the lines in both of the sets
replacing one or more white characters in a row, to one line break...
taking the 4th to 7th character of each line and print them in one line with comma as a delimiter
these are not the best examples, but generally any kind of parsing, manipulating and query of texts.
it's very often that the task is extremely easy in any programing language, but it is just to frustrating to open the IDE of such language....
i'm looking to some way to write code (with intelisence/autocomplete), in an easy fast window...... with simple input and output textboxes....
do you understand my need? can you think of anything that can help?
i know some of the problems can be solved using excel.. but i really prefer some good old programing.... unless someone is strongly believe i'm wrong.
if i will build something myself, there will be an option to add any amount of unlimited multiline textboxes. they'll be automatically named, although the name is changeable (the names will be the the name of the variables).
you can as well add any number of output textboxes that have names...
and you have the editor window, in which you write the procedure..... and it will have some interactive intelisence like interface...
can you see what i'm saying? do you know anything similar?
Seems like Python would be fine for this.
Has an interactive keyboard interface, quite nice abstraction facilities,
and strings as objects with good libraries for processing such strings.
It sounds like a lot of what you want can be handled with regular expressions using sed, awk, or perl in a standard console. Autocomplete will be pretty limited, but your scripts will be short anyway - to deal with your third case above, for example:
sed 's/^...\(....\).*/\1/g' < input.txt | tr "\n" ',' > output.csv
What you can do is use an interactive regex tester. There's many online like this one.
You could also look into tools like Data Wrangler from Stanford, which are designed to be more accesible but as powerful as traditional shell tools.
(Note that your first issue - intersecting sets of lines - is a bit different, and would be solved in the shell with comm. This page has a good explanation of how to use comm to perform set operations like "all the files in this file not in this file" or "only the files in this file also in this other file".)
I realized, when just asking a question, I don't understand all the components that are part of the coding process.
This seems a silly question, but I can't find a definitive answer on Google, Wiki, nothing.
What exactly are all the parts called, and how do they work and intertwine? I'm talking whatever you type code into, whatever checks that for errors, compiles it, and runs it.
I'd appreciate any links, repeats, etc. I apologize for such a bland, stupid question.
EDIT: Well, I'm trying to start Perl, so anything about Perl would help. Like, how to use Notepad++ and eventually compile Perl.
Write code
Run code in one of two ways[*]
Compiled languages (C, C++, D, Java, C#)
Compile the code into an executable file with the compiler tool.
Run the executable
Interpreted languages (Perl Python Ruby Lua Haskell Lisp & more)
Run the code in an interpreter, e.g., perl foo.pl
Debug code.
edit: Since the question was refined to be the Perl development cycle...
You will need an editor and a 'shell', which is used to command the system with. In particular, you want a 'command-line interface'. On Windows, you start this with running cmd.exe on the Run dialog (Windows + R is the shortcut).
You see a strange black and white box with a blinking cursor, reminding you of ancient systems redolent of gurus and wizards. You panic and refer to Google, getting a web page. Finding the command to change directory and list files is recommended...
Upon arriving at the directory where you stored your Perl file, you issue the command perl myfilename.pl, where myfile.pl is the file you saved. As is common for programming, you find some errors that appear to be incomprehensible, and you refer to Stackoverflow.com once again...
* I have elided, glossed, and moved past many of the details, as this is an introductory question. A full discussion is known as "senior-level course on compilers".
I wrote an application in VB.NET and since I charge by the line, I would like to calculate how many lines I wrote. I have about 100 different Visual Basic files with my code. How do I count all the lines?
You could do a regex search for a line-break char that isn't followed by another linebreak (excluding blank lines)
Alternatively there's this app http://cloc.sourceforge.net/ (I haven't used it, I just found it)
On the command line:
(for /r %x in (*.vb) do #type "%x") | find /v /c ""
If you're using Visual Studio 2005 or earlier then there's a line counter add-in at WndTabs.com.
This can be done in PowerShell:
Example 1
Example 2
I also recommend the excellent NDepends suite as well. For one, I think it will clearly illustrate why lines of code is a very difficult thing to measure, and not necessarily a good measure of quality, or amount of work in a codebase.
Line Counter on SourceForge is a VB.NET application that counts the lines for you in your application. I was going to say you could write your own VB.NET application to do this, but luckily it has already been done. It's sweet how the Internet works that way.
Also, charging by the line? Newline must be your friend! LOL.
I really hope you're joking about charging by the line, but if not, there are a number of prepackaged free utilities and scripts that will do these sort of quick-and-dirty metrics for you, like the Line Count Utility.
P.S. Please consider a different way of charging your customers!
I have just come up to this question myself. Although this is a 10 yr old question.
Well try this, on your VB.NET, just go to ANALYZE menu and just click Calculate Code Metrics for your project and your done. :)
On a Unix-like platform:
find . -name *.vb | xargs wc -l