variables problem ! (please help a noob)

Hi guys,
I am new on this forum and I'm a beginner in programming in C and today I feel the need to ask for your help because I am stuck on something that really annoys me a lot.
I have an issue concerning variables that keep letters (sorry if the terms are not correct, I am french and I don't know how it is called in english). I use code blocks IDE
Anyway, have a look on this and please tell me why the "error..." message appears TWICE when I don't press 'r' but an other letter instead!?

Code:

---

#include <stdio.h>
#include <stdlib.h>


int main()
{
    char menu=0;

    printf("press 'r' \n");
    scanf("%c", &menu);
    while (menu !='r')
    {
        printf("Error!! \n ");
        scanf("%c", &menu);

    }
  return 0;

}

---

If you type in say
x<return>

Your scanf with %c is going to fetch 'x' on the first call, and then '\n' on the second call. Both of which result in the error message being printed.

If you always use fgets() to read a line of input, then use sscanf() (or anything else you like) on the resulting buffer, you'll have a lot less difficulty in dealing with a lot of the less obvious side effects of using raw scanf calls.

ok, thx for your answer. Could you write the code the way it is supposed to be please so I can understand clearly what you say?
I am just starting programming so these terms are quite obscure to me for the moment :)

Try adding after each scanf

printf("The key pressed is %c (%d)\n", menu, menu );

I did what you told me but look what it does:

Code:

---

press 'r'
i
the key pressed is i (105)
error!!
 the key pressed is
(10)
Error!!

---

Good - do you understand now where the two characters are coming from (and what they are)?

sorry I don't know

So rather than typing in a single letter, try a string like
hello<return>

or
this is wrong<return>

Quote:

---

Originally Posted by bingofuel

sorry I don't know

---

FWIW... Salem is showing you how to add diagnostic statements to your code, to help discover what the problem is. They're not intended to fix anything, their job is to reveal the errors for you. When the program is complete, you can remove them.

You already know that what you got is not what you want... Follow Salem's advice to find out why.

(Hi Salem!)

Im just going to state that you shouldnt use while in this situation, instead use if/else.