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Aug 27th, 2004

Help in Input output C files

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Hi guys / girls i am new in this forum and i hope you could help me in this problem.

i programmed a link list which stores some information one of them is strings and i entered them using the function gets(); instead of scanf(); to enable the program to read the space character, and at the termination of the program i call a function to save the linked list to a file but the problem aarise when i return and open the file and load the link list from the file to Main Memmory this what happen:

suppose i entered the string "aaaa bbbb" note that there is a space..
when i close the program and then reexecute it and use the function
fscanf(); to read from a file it consider "aaaa" a string and "bbbb" another string it don't consider them as one string.

please help me.. :rolleyes: :rolleyes: :rolleyes:

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wild_potatos

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Aug 27th, 2004

Re: Help in Input output C files

Quote originally posted by wild_potatos ...

Hi guys / girls i am new in this forum and i hope you could help me in this problem.

i programmed a link list which stores some information one of them is strings and i entered them using the function gets(); instead of scanf(); to enable the program to read the space character, and at the termination of the program i call a function to save the linked list to a file but the problem aarise when i return and open the file and load the link list from the file to Main Memmory this what happen:

suppose i entered the string "aaaa bbbb" note that there is a space..
when i close the program and then reexecute it and use the function
fscanf(); to read from a file it consider "aaaa" a string and "bbbb" another string it don't consider them as one string.

please help me.. :rolleyes: :rolleyes: :rolleyes:

Avoid both gets and scanf -- with which it looks like you discovered that the %s specifier is whitespace delimited. Instead use fgets to read a whole line, followed by sscanf to pick off the parameters (or other means since you've already got one big string) -- and don't forget to specify the maximum width with the %s (that is, %10s for example).

Dave Sinkula

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Aug 27th, 2004

Re: Help in Input output C files

Yea, better use fstreams they are much better and easier to use.Here's a link:
http://www.daniweb.com/techtalkforums/thread6542.html

Try posting some of your code too.We might be able to help you better then.

FireNet

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Aug 27th, 2004

Re: Help in Input output C files

could you dave please give me an example about fgets and sscanf
i would notice that i used structers in my code

wild_potatos

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Aug 27th, 2004

Re: Help in Input output C files

An example:

C Syntax (Toggle Plain Text)
#include <stdio.h>
 
  struct name
  {
     char first[16];
     char last[32];
  };
 
  int main(void)
  {
     char line [ BUFSIZ ];
     fputs("Name (First Last)? ", stdout);
     fflush(stdout);
     if ( fgets(line, sizeof line, stdin) )
     {
  	  struct name myname;
  	  if ( sscanf(line, "%15s%31s", myname.first, myname.last) == 2 )
  	  {
  		 printf("myname: first = \"%s\", last = \"%s\"\n",
  				myname.first, myname.last);
  	  }
     }
     return 0;
  }
 
  /* my output
  Name (First Last)? Dave Sinkula
  myname: first = "Dave", last = "Sinkula"
  */
#include <stdio.h>
  
  struct name
  {
     char first[16];
     char last[32];
  };
  
  int main(void)
  {
     char line [ BUFSIZ ];
     fputs("Name (First Last)? ", stdout);
     fflush(stdout);
     if ( fgets(line, sizeof line, stdin) )
     {
  	  struct name myname;
  	  if ( sscanf(line, "%15s%31s", myname.first, myname.last) == 2 )
  	  {
  		 printf("myname: first = \"%s\", last = \"%s\"\n",
  				myname.first, myname.last);
  	  }
     }
     return 0;
  }
  
  /* my output
  Name (First Last)? Dave Sinkula
  myname: first = "Dave", last = "Sinkula"
  */

Dave Sinkula

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Aug 29th, 2004

Re: Help in Input output C files

i am sorry dave but i don't know you may not understanded me or vice versa i want to save the values in a file outside C for example "wild_potatos.dat"

wild_potatos

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Aug 29th, 2004

Re: Help in Input output C files

Files are streams just like stdin and stdout. Surely you can open a file; and surely you could using fprintf instead of printf without much issue -- so what code can you post that does not behave as you'd like?

Dave Sinkula

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This thread is more than three months old

No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.

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