Thread: Manipulating a read-in file in C

Question 12.2
You just need to check fscanf() return value for EOF;

My 945 page textbook has exactly 2 sentences on feof(), which really don't appear to help. I am going to try to get this without bothering you every 15 minutes until I have something substantial to show. Frustated. Thank you Tater

Read the manual!
Just google for man fscanf.

Originally Posted by JoshD75

Yea, thank you Tater. That is pretty darn obvious after seeing it in code and reading it line by line....works perfectly. However it does NOT print the last line twice, at least on my end....

Ok just to be clear... it gets all three lines of our test file correctly?

Attachment 10548

This is important before we move on...

Ok so next step is to calculate the weighted averages as you said. Of course I am still game, and I appreciate you taking the time to explain this to me step by step. Much better than someone doing it for me, or guessing! Ok, so any hints as to the next step? Thank you again, this is invaluable to me as a learning experience...

No worries... Now I need to know how you're calculating the averages ... the obvious way is to add everything up and divide... but you already explained it's not quite that obvious, so what's the formula?

Thanks for the suggestion Bayint... but there's a reason not to do it that way just yet...

Originally Posted by CommonTater

Ok just to be clear... it gets all three lines of our test file correctly?

Attachment 10548

This is important before we move on...



No worries... Now I need to know how you're calculating the averages ... the obvious way is to add everything up and divide... but you already explained it's not quite that obvious, so what's the formula?

Correct Tater, all 3 lines of data show up exactly like yours shown above.

The formula is q1-q4 are each valued at .10%, midterm is .25% and final is .35%

Thanks again...

I see you edited out your "try to do this with integers if you can". That confused me originally, as the result would be in Float I would think, "85.50" or whatever. I am going to work on this later and get back to you. Again, thank you!

Got it! I think? I am going out for a bit and will check your response when I get back. Thank you again!

Code:

#include <stdio.h>
#include <string.h>

int main( void )
{
  
  char firstname [50];
  char lastname [50];
  int q1,q2,q3,q4,mid,final;
  float grade;
  FILE *fp;
  char my_filename_input[] = "C:\\Documents and Settings\\denauljo\\Desktop\\Final_Input.txt";

  fp=fopen (my_filename_input, "r");

  while (! feof(fp))
  {  
  fscanf (fp,"%s %s %d,%d,%d,%d,%d,%d",firstname,lastname,&q1, &q2, &q3,&q4,&mid,&final);
  grade = (q1 * 0.1) + (q2 * 0.1) + (q3 * 0.1) + (q4 * 0.1) + (mid * 0.25) + (final * 0.35);
  printf("%s %s %.2f\n", firstname,lastname, grade);
 
  // printf ("%s %s %d %d %d %d %d %d\n", firstname,lastname,q1, q2, q3,q4,mid,final);
  }

  fclose(fp);
  return 0;
}

Excellent... i would have done it a little differently...

Code:

printf ("%s %s %d %d %d %d %d %d  Average = %.2f\n", firstname,lastname,q1, q2, q3,q4,mid,final, grade);

//printf("%s %s %.2f\n", firstname,lastname, grade);

What you have isn't wrong by any means... I just like to see all the information on screen while debugging.
We'll need that commented out line, so don't delete it....

So... before we move on to the next step, do a few runs with our test file, make sure the results are consistent... and then we'll go after that bug I mentioned.

Works fine Tater, I added some names and some scores and it works as intented. To mix it up a bit, let me tell you what I think needs to happen next and you can tell me if I am way off or on the right track. The next step (besides the bug you mentioned) I believe is to add an if else() loop statement beneath arithmetic line, breaking it down into letter grades. 70-79, 80-89, 90-100 = C, B , A or whatever.

Is that the next step? Once that is complete then we configure the output file?

Thanks

Yeah we can do letter grades next if you like. In fact, the bug can (should?) wait till we're done with that --even till after we do the file write since it involves all the steps.

So show me how you'd do letter grades, without disturbing the working code we have now...