Inputting strings from a file

**Mystic_Skies** · 11-17-2004

Hello everyone. I'm having a problem in a program I'm working on and I broke the program up into this small bit here. I've done searches on the forum and tried to input this file from what I've seen on other posts but what I cannot figure out is why the strings are not getting read correctly. Can anyone help?

The error is that it's not printing the first 2 strings being read. The last (which is a char) gets read and prints out just fine strangely enough.

Input:

Code:

PROGA      0000  C
LISTB      0000  I
ENDB       0000  I
P          0048  R
BR         104B  R
B1         104E  R
B2         1061  R

Code:

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

FILE *st_fptr, 
     *fopen();

int main( void )
{
   char temp_name[6];
   char temp_value_str[4];
   char temp_type;
   
   if ( ( st_fptr = fopen ( "symtab.txt", "r" ) ) == NULL )
   {
       printf ( "Can't open 'symtab.txt' file!\n" );
       getchar();
       exit(1);
   }  

   while ( !feof ( st_fptr ) )
   {
      fscanf ( st_fptr, "%s%s%s", temp_name, temp_value_str, &temp_type );
      printf ( "name: %s\n", temp_name );
      printf ( "string: %s\n", temp_value_str );
      printf ( "type: %c\n\n", temp_type );
   }  
   
   printf ( "Press return to continue..." );
   getchar();
   
   return 0;   
}

**itsme86** · 11-17-2004

One thing I notice is that temp_value_str isn't large enough to hold the string. It needs to have at least 5 elements for there to be enough space.

**itsme86** · 11-17-2004

Also, temp_type is a char, but you're using %s instead of %c.

**Mystic_Skies** · 11-17-2004

Hey thanks

I changed the second string to hold 5, and %s to %c and now the first 2 strings display but the last one won't anymore. Strange.. I don't get that.

**Dave_Sinkula** · 11-17-2004

How about something like this?

Code:

#include <stdio.h>

int main( void )
{
   FILE *file = fopen ( "file.txt", "r" );
   if ( file )
   {
      char name[6], value[5], type[2];
      while ( fscanf ( file, "%5s%4s%1s", name, value, type ) == 3 )
      {
         printf ( "name:   %s\n",   name  );
         printf ( "string: %s\n",   value );
         printf ( "type:   %s\n\n", type  );
      }
   }
   return 0;
}

[edit]I chose a string for the third parameter because the %c directive is not whitespace-delimited like %s.

**Mystic_Skies** · 11-17-2004

Hey Dave. That solution looks like it will work but the only question I have is that I need "type" to just be a single char and you've defined it as an array of 2. Can fscanf read just a single char correctly?

One more question also... If i'm reading in a string should I always put those numbers in between the % and the s the way you have shown?

**Dave_Sinkula** · 11-17-2004

Originally Posted by Mystic_Skies

Hey Dave. That solution looks like it will work but the only question I have is that I need "type" to just be a single char and you've defined it as an array of 2. Can fscanf read just a single char correctly?

Yes.

Code:

      char name[6], value[5], type;
      while ( fscanf ( file, "%5s%4s %c", name, value, &type ) == 3 )
      {
         printf ( "name:   %s\n",   name  );
         printf ( "string: %s\n",   value );
         printf ( "type:   %c\n\n", type  );
      }

Originally Posted by Mystic_Skies

One more question also... If i'm reading in a string should I always put those numbers in between the % and the s the way you have shown?

Yes.

**Mystic_Skies** · 11-17-2004

Thanks for the help. Problem solved.

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