Thread: Probably simple mistake (newbie)

Hi,

I just started with C like 1 week ago and Ive never coded in my life so bear with me as I always try to code stuff from the top of my head that Ive already learned so its really just a very simple code ...

Code:

#include<stdio.h>

int main(void)
{

  char c;

  //ask user

  while (!(c == 'y' || c == 'Y' || c == 'n' || c == 'N')) {
    printf("Do you agree?: ");
    scanf("%c", &c);

    if (c == 'y' || c == 'Y')
      printf("I agree\n");

    else if(c == 'n' || c == 'N')
        printf("I disagree\n");
  }

}

The purpose of this code is to ask the user if he "Agrees" and if he types in anything else than "Y/y or N/n" it asks the user again in a loop.

Now the problem is that if you enter any other charakter than "Y/y /N/n" it always prints "Do you agree?: " twice in a row and I cant figure out why.

Thanks in advance.

Welcome to the forum.

First thing, when you paste code, make sure you use "copy as text" from your IDE and/or "paste as text" in your browser.
The colour markup that comes along for the ride from most IDEs is pathetic.

> char c;
Initialise your variables.
If by chance the random initialisation matches your loop exit condition, you're stuck.

> scanf("%c", &c);
%c is rather special in the scanf conversions in that it respects white space (which includes newlines).
So typically you go round your loop twice, once with c='Y' say, and then again with c='\n'.

If you want to avoid this, add a space to the format.

Code:

scanf(" %c", &c);