scanf(), ungetc() behaviour.

[Argento]

I was curious at the start about how ungetc() returns the character to the
stream, so i did the following coding. Things work as expected except if I
change the scanf("%c",&j) to scanf("%d",&j). I don't understand how could
scanf() affect the content of i[0] and i[1]. Can someone tell me why?

#include <stdio.h>
#include <ctype.h>

void main()
{
char i[2], j;
printf("Please input a two digit number:");
i[0]= getchar();
i[1]= getchar();
ungetc(i[1],stdin);
ungetc(i[0],stdin);
scanf("%c", &j); //scanf("%d",&j);
fflush(stdin);
printf("\nYou entered %d in decimal and %c in character mode for
i[0]",i[0],i[0]);
printf("\nYou entered %d in decimal and %c in character mode for
i[1]",i[1],i[1]);
printf("\nYou entered %d in decimal and %c in character mode for j",j,j);

getchar();

}

[Richard Bos]

CBFalconer <cb********@yah oo.comwrote:

Richard Heathfield wrote:

Christopher Layne said:

Richard Heathfield wrote:

The routine is the more useful if its return value can be used
in a simple on/off test in a loop - which you pick is a matter
of taste, really. Hence the second change. The first change is
because we really, really, really mustn't enshrine this
ridiculous use of the word "flush" to describe getting rid of
*input*!

Richard 'discards' his toilet.

No, Richard regards the contents of the toilet bowl as output,
so the word "flush" is appropriate.

But you don't flush a tap (or, if you are Usanian, a faucet).

But you do flush an IV.

Yes, you flush _it_ until it's empty. You don't flush your vein until
you're full.

Having had them on and off for the past 3 months I am now an expert.

That's not good news. Hope it does at least work.

Richard

[Charles Richmond]

CBFalconer wrote:

>
Richard Heathfield wrote:

Christopher Layne said:

Richard Heathfield wrote:

The routine is the more useful if its return value can be used
in a simple on/off test in a loop - which you pick is a matter
of taste, really. Hence the second change. The first change is
because we really, really, really mustn't enshrine this
ridiculous use of the word "flush" to describe getting rid of
*input*!

Richard 'discards' his toilet.

No, Richard regards the contents of the toilet bowl as output,
so the word "flush" is appropriate.

But you don't flush a tap (or, if you are Usanian, a faucet).

But you do flush an IV. Having had them on and off for the past 3
months I am now an expert.

A couple of years ago, I was in a hospital and had IV's
and a PICK line. It is *not* pleasant. My PICK line clogged
because the dufus nurses did *not* flush it often enough.
You have to take charge of your own treatment to a great
degree. I am sure you already know this.

--
+----------------------------------------------------------------+
| Charles and Francis Richmond richmond at plano dot net |
+----------------------------------------------------------------+

[pete]

Charles Richmond wrote:

>
CBFalconer wrote:

Richard Heathfield wrote:

Christopher Layne said:
>Richard Heathfield wrote:
>>
>>The routine is the more useful if its return value can be used
>>in a simple on/off test in a loop - which you pick is a matter
>>of taste, really. Hence the second change. The first change is
>>because we really, really, really mustn't enshrine this
>>ridiculous use of the word "flush" to describe getting rid of
>>*input*!
>>
>Richard 'discards' his toilet.
>
No, Richard regards the contents of the toilet bowl as output,
so the word "flush" is appropriate.
>
But you don't flush a tap (or, if you are Usanian, a faucet).

But you do flush an IV. Having had them on and off for the past 3
months I am now an expert.

I like the word "drain" as the antonym of "flush",
for describing getting rid of *input*.

--
pete