Thread: using scanf

Hey, i have a question.
I am using scanf to read in a paragraph from the keyboard and break it up into words.
I am close to doing this but I cant figure out how to make my loop stop.
When there are no more words, I would like my loop to stop, but I dont know how to check for that.
Here is what I ahve so far, any help would be appreciated.

Code:

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

#define MAX_SIZE 16

int main(void)
{

/* char array to hold each word with a max word size of 15 */
 char words[MAX_SIZE];

	printf("Enter a line of text: "); 

/* this loop prints each word one after the other from left to right */
	while(scanf("%s", words)!= 0) {
            printf("%s\n", words);
		/*if there are no more words, 
		   end loop*/
	}
}

How do you check to see if there are any more words left?
Also how can I equal the value of scanf("%s", words) to 1 so the loop stops.
Thanks

Use fgets to read in the entire line, then use sscanf to read from there.

scanf returns the number of successful conversions. If you're reading one word at a time, the number of conversions should be 1, so this will do what you want:

Code:

while ( scanf ( "%s", words ) == 1 )
  printf ( "%s\n", words );

Nothing changed. The loop still doesnt end. It just waits for more input.

On Windows, press Control-Z, on Linux, press Control-D.

Originally Posted by tabstop

Use fgets to read in the entire line, then use sscanf to read from there.

That is a better way, that I also recommend. Note that with fgets you also read the newline ('\n') character.

Originally Posted by robwhit

On Windows, press Control-Z, on Linux, press Control-D.

I need the loop to do that.

This is a very simple task, why cant anyone give me a straight answer?

example input:

hello how are you?

example output: //correct ouput

hello
how
are
you?
//END program

Right now I have output which is incorrect:

hello
how
are
you?
_ //waitting for more input

how do I terminate the loop after Ive read the last word?

Why not just use fgets() to read a line at a time, and scan the line using sscanf() (If someone already suggested that, my bad I only read the first and last post).

Originally Posted by gp364481

I need the loop to do that.

You need a loop to press keys on a keyboard?

I think what the OP is trying to say is that he wants to automate the process of breaking the loop. Now that I opted to read other posts, I am the third person to suggest using fgets(). Plus if you just do as Prelude so eligantly suggested and specifically check for a valid input, you won't loop once data is input by the user. Just redesign your loop, my friend.

Example:

Code:

printf("Enter a line of text: (Or if you are done and a Windows user, press CTRL+Z, unless of course you are on *nix or Mac. If that is the case, press CTRL+D)");

Pretty smooth programming eh?