Thread: While != EOF loop question

I've written the following code and I want it to keep looping around collecting input (only asking the question once at the start) until the user uses EOF (aka ctrl+d) to "say I have no more input". I have a do while loop but obviously the while part is wrong but I'm not sure what needs to be != EOF if not number? Any suggestions?
Thanks.

Code:

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

int main()
{
   int number;
   char unit[3];

   printf("Enter a number between 0-200 followed by its units: ");
   do
   {
      scanf("%d%60s", &number, unit);
      if (strlen(unit) > 2)
      {
          printf("Units are too long\n");
      }
      else if (number < 0 || number > 200)
      {
          printf("Number too large\n");
      }
      else
      {
          printf("Entered number: %d\tEntered unit:%s\n", number, unit);
      }
   } while (number != EOF);

   return(0);
}

scanf doesn't output EOF as a token. scanf will only *return* EOF. see the prototype:

Code:

int scanf ( const char * format [ , argument , ...] );

so assign the return value to a variable, and test that against EOF

Originally Posted by jephthah

scanf doesn't output EOF as a token. scanf will only *return* EOF. see the prototype:

Code:

int scanf ( const char * format [ , argument , ...] );

so assign the return value to a variable, and test that against EOF

Thanks, I got it working using something like this

Code:

testForEOF = scanf("%d%s", &number, unit);
while (testFor EOF > 0)
{
   ...
}

I can't seem to find this anywhere, but is EOF always returned as -1? ie could I change the while so that it was this and have it always work or could the return value be -5 for EOF?

Code:

while (testForEOF != -1)

Haven't I seen this before? C while != EOF question? - Yahoo! Answers

Exact same question and code :P.

Originally Posted by User Name:

Haven't I seen this before? C while != EOF question? - Yahoo! Answers

Exact same question and code :P.

Yeah, and if you saw the response I got it was go ask this question in a real computer forum, which is here, which is why I reposted the same question, pretty much word for word before deleting the other post and it's not so helpful response.

I can't make you understand, and you reposted before I responded :P. But honestly, Yahoo Answers isn't good for anything computer/programming related, you're better off asking here, unless you need to ask how the power button works, they might be able to answer that . Sorry I couldn't help before.

yahoo answers is good for something.

mostly just lulz.

but hey. what do you expect?