need urgent help with understanding a little c code

[Fat Tone]

Hi

I need to get this short c-code working for a colleague. He has compiled it to work on his mac. You can see the source at http://www.physionet.org/physiotools/dfa/dfa.c and you can read about the program at http://www.physionet.org/physiotools/dfa/dfa-1.htm

I know virtually nothing about c and would appreciate some guidance.

I have replaced the code that reads the command line arguments with printf & scanf instructions to prompt for inputs and this works fine.

Then we come to the difficult bit: We want to read in a list of data from a text file. Currently it uses the 'standard input' which I think means the keyboard. The program keeps looping around accepting values, but we can't seem to terminate the list input. This is the line in question: while (scanf("%lf", &y) == 1) { ...


Can someone please point me in the right direction? Initially to get the keyboard input working, and possibly to read a file instead?

Many thanks in advance.

Tony.

[cjolley]

I'm a little rusty, but to get you started:
Standard input is just about any stream directed at the program.

Try Ctrl-Z to end the input from a keyboard
or "dfa < input.txt" to use input.txt as a stream source
or "type input.txt | dfa.exe" to pipe the text from the file into the program //this one won't work if it contains much but regular text.

<i see invizo-text is still working>
chuck

[Fat Tone]

Thanks Chuck.

He's running OS9.1 and I think just wants to start the compiled code and then type in the name of the data file - that's why he had me mod the command line arguments into prompts.

The input is only a stream of numbers, as are the arguments now, so I guess we could create a file that contains the arguments and the data and give your suggestions a shot! Presumably icon shortcuts on macs can be modified in the same way as on PCs?

Thanks again

Tony.

[cjolley]

Here is a skeleton example of how to open & read a file line by line.
Assuming each data point is on a separate line in the file & not realy a stream.

#include &ltmalloc.h&gt 
#include &ltstdio.h&gt

#define BUFFSIZE 256

int skeleton_input(char* FILE_NAME)
{
	FILE  *InFile;
	char  *linebuf;

	if ((InFile = fopen(FILE_NAME, "r")) != NULL)
	{
		linebuf = calloc(BUFFSIZE + 1, 1);
		while(fgets(linebuf, BUFFSIZE, InFile))
		{
                                      STICK THE DATA IN THE ARRAY HERE
		}
		fclose(InFile);
		free(linebuf);
	}
	else
	{
		printf("%s%s", "Can't open ", FILE_NAME);
	}
	return 0;
}

chuck

PS Surely someone less rusty than me is learking around here somewhere.

EDIT - thanks KeiFront

[KeiFront]

Re: need urgent help with understanding a little c code

This is the line in question: while (scanf("%lf", &y) == 1) { ...

This line will read in numeric data until a character or other symbol is detected (e.g. 5 5.63 6 9 8 10 A).



if ((InFile = FILE_NAME, "r")) != NULL)

should be

if (InFile = fopen(FILE_NAME, "r")) != NULL)

[cjolley]

Re: Re: need urgent help with understanding a little c code

Originally posted by KeiFront


This line will read in numeric data until a character or other symbol is detected (e.g. 5 5.63 6 9 8 10 A).



if ((InFile = FILE_NAME, "r")) != NULL)

should be

if (InFile = fopen(FILE_NAME, "r")) != NULL)

Heh.
I was hurridly cuting & pasteing from a larger program so as not to be confusing.
chuck

[Fat Tone]

Thanks for the suggestions guys. Much appreciated.

T.

[Wombat]

Usually Ctrl-D is the way to type the EndOfFile marker.

[Gurm]

Shouldn't that be:

if ((InFile = fopen(FILE_NAME, "r")) != NULL)

???

- Gurm

[cjolley]

Wombat- In a dos box on XP ctrl-z works, I tried it
Is ctrl-D a Mac thing?

GURM- That's what I changed the code to.

Tony- Look up, I changed the code.

chuck


PS It's amazing what can distract one from work

[cjolley]

How the heck do you show a <<>>s for an include?
They keep vanishing.
chuck

[Wombat]

The HTML code is (ampersand)lt and (ampersand)gt

&lt&lt&gt&gt

[Gurm]

&ltI have no idea &lt&gt what you're talking &lt&gt about!&gt

- Gurm

[cjolley]

Ahh.... much better

Tony- look up, I changed the code again

chuck

PS Why doesn't the html parser ignore that stuff untill it gets to the /code tag?

[Wombat]

Almost better, Try cheating. After the lt, add an HTML comment < ! >

The UBB parser is funky.