fprintf question

[countdrak]

The following code works fine.

FILE *result;
result = fopen ("results.txt", "r"); 
fprintf(result, "raw array is as follows\n");//line 1
for (k=0; k<100; k++)
{
   temp[k] = raw[k];
   fprintf(result, "%lf\n", raw[k]);
}
fclose(result);
[\code]

k, raw and temp are initialized and everything. Works fine.

But the following code
[code]
FILE *result;
result = fopen ("results.txt", "r");
fprintf(result, "raw array is as follows\n");//line 1
for (k=0; k<100; k++)
{
   temp[k] = raw[k];
   if(raw[k] !=0)
   {
      fprintf(result, "%lf\n", raw[k]);
   }
}
fclose(result);
[\code]

This does not even print line 1. I get an empty file. Any clues? Im tearing my hair over this.

 

[DaveSinkula]

http://www.eskimo.com/~scs/C-faq/q14.5.html

 

[SamBones]

I don't see the difference in the two code samples. Did you copy/paste correctly? (Also, it's a "[ignore][/code][/ignore]" to terminate the code block, not a "[ignore][\code][/ignore]").

First, you are opening the file for "read" only. Change your [tt]fopen[/tt] to...

result = fopen ("results.txt", "w");

Hope this helps.

 

[DaveSinkula]

Open the file for writing instead of reading.

 

[countdrak]

Well, it seems that was not the problem, "r" was a typo in my post..should have been "w". Thanks Dave for that faq. Very interesting.

 

[SamBones]

So you want help with code that you haven't posted for us?

Can you post the real code?

 

[countdrak]

No, I figured it out. Pointer problem. Thanks for your help though.