scanf() asterisk.

[denc4]

Hi.

I'm learning ANSI C for a few days now. I use Microsoft C 7.0 as a compiler, my target platform is DOS.
I'm having trouble grasping the idea of the asterisk in the scanf() function..

Why can't:

scanf("%i %*i %i",&value1,&value2,&value3);

be written as:

scanf("%i %i",&value1,&value2);

these two commands basically yield the same result, right?
then why bother with the asterisk to begin with?

thanks.

 

[Salem]

> scanf("%i %*i %i",&value1,&value2,&value3);
Which is wrong anyway, it should be
[tt]scanf("%i %*i %i",&value1,&value2);[/tt]

> scanf("%i %i",&value1,&value2);
Because this expects you to type in
[tt]12 34[/tt]

Whereas the assignment suppressed version expects
[tt]12 9999 34[/tt]

Both result in 12 and 34 being stored in the conversion results.

--

 

[chipperMDW]

Consider that, instead of reading input from a user sitting at the keyboard, it might be reading the input from a file with predefined fields. You might only want the first and third fields, and not care about the second.

 

[denc4]

ok, but why ask the user to input 3 strings, if only 2 are stored?
in other words: why would you let the user input a string when it won't be assigned to a variable anyway?

 

[denc4]

that makes sense chipperMDW, i haven't gotten to the file I/O operations in my book yet.

so, when getting input from the keyboard the asterisk is actually useless.

thanx.

 

[cpjust]

Hmm... I've never heard about that asterisk thing before. I would have just used a 3rd int and just ignored what was stored in it.