Outputting to a text file...

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June 9th, 2004, 11:51 PM

medo7777

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Join Date: Apr 2004

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Outputting to a text file...

Hello,

I'm having trouble getting this bit of code to work properly..
What its supposed to do, is get all the data that is entered and output it into a sort of table, in a text file...
my problem tho, is that im getting really wierd outputs and i don't really know what's wrong.
Yes, i'm new to C.. and this is the 1st time i've tried doing anything like this.. so forgive my lack of knowledge

Any help would be greatly appreciated.

Thanks,
Mark

PHP Code:


		
			
/*

      file:  student.cpp

      date:  8th June 2004

*/



#include <conio.h>

#include <stdio.h>





int main ()

{

    char  name[21];

    int score, count;

    float average, total;

    

  FILE *fp;

  fp = fopen("scores.txt","w");

  



  printf("Enter Name: ");

  gets(name);



  fprintf(fp,"Name                   Score     Score     Score     Score     Score            Average\n");

  fprintf(fp,"                           1         2         3         4         5                   \n");

  fprintf(fp,"---------------------------------------------------------------------------------------\n");

  

  while(name[0] != NULL)

    {

      fprintf(fp,"%s", name);

      total=0;

      count=0;

      printf("Enter Score: ");

      scanf("%d", &score);

        while(score != -1)

          {

            total += score;

            ++count;

              if(count<5)

                 {

                  printf("Enter Score: ");

                  scanf("%d", &score);

                 }

                else

                  score = -1;

          }

      average = total / count;

      printf("%.2f\n", average);

      fflush(stdin);

      printf("Enter Name: ");

      gets(name);

    }

    

  fprintf(fp,"%s            %d        %d        %d        %d        %d        %2.2f\n", name, score);





fclose(fp);

return 0;

}

June 10th, 2004, 12:15 AM

Dave Sinkula

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Sorry, I didn't try to build it -- but the following links jump to mind.

June 10th, 2004, 12:20 AM

dwise1_aol

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while(name[0] != NULL)

NULL is a zero pointer.
name[0] is a char .
name is a pointer to a char array, but it does have a non-NULL value.

You appear to be wanting to test for name not being an empty string. This could be done with these possible lines:
while(name[0] != '\0') /* is first char the null-terminator? */
while(strcmp(name,"") /* compare name with an empty string */
while(strlen(name)) /* if length isn't zero, is not empty */

strlen() and strcmp() both require the string.h header file.

Also, are you sure that you're opening the file in text mode. There's a global filemode variable that defines the default. Personally, I always explicitly open my files with "wt" or "wb".

And gets does not protect against buffer overflow, making it a security hole just waiting to happen, or at least a way to crash the program unexpectedly. It is preferable to use fgets with the stdin standard file. However, be aware that fgets does not remove the '\n' from the input string like gets does.

Last edited by dwise1_aol : June 10th, 2004 at 12:26 AM.

June 10th, 2004, 05:40 AM

Ancient Dragon

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Location: near St. Louis Illinois

Posts: 3,288

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your program produces the wrong file because the fprintf() is in the wrong place.

Code:


	  fprintf(fp,"%s            %d        %d        %d        %d        %d        %2.2f\n", name, score); 

      average = total / count; 
      printf("%.2f\n", average); 
      fflush(stdin); 
      printf("Enter Name: "); 
     fgets(name,sizeof(name),stdin); 
    }

Outputting to a text file...

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