do{}while loop trouble

Where did I go wrong with this code for my do while loop?

Code:

int main()
{
	char response;	

	do
	{
		/* My main code would be here */

		printf("\n\n\nDo you wish to convert another number? (y) or (n): ");
		scanf("%c", &response);

		while(!(response == 'y' || response == 'Y' || response == 'n' || response == 'N'))
		{
			printf("\nPlease enter (y) or (n): ");
			scanf("%c", &response);			
		}
	} while(response == 'y' || response == 'Y');

	return 0;
}

The output when the program goes to the do while loop is:

Code:

Do you wish to convert another number? (y) or (n):
Please enter (y) or (n):

For some reason that I do not see the program skips the first scanf() and enters the while loop going instead to the second scanf(). What am I doing wrong?

Also does C have and equal to the C++ ignore function? I would normally code the response input as:

Code:

cin >> response;
cin.ignore(100, '\n');

I do not know if C has something similar to this for garbage clean-up.

No, it doesn't have a cleanup method. You can do one of a few things:

1) Use fgets, read into a buffer, and get it from there.
2) Use something like:

Code:

void clean( void )
{
    int c;
    while( (c=fgetc()) != '\n' && c != EOF )
        ;
}

3)You can modify parameters to scanf to ignore the newline.

Code:

scanf("%c*[^\n]*%c", &response );

There are a few others, but those should do.

Quzah.

Originally posted by quzah
3)You can modify parameters to scanf to ignore the newline.

Code:

scanf("%c*[^\n]*%c", &response );

cool!! Is there a place where I can learn more about these parameters? (i.e. on the web/any book ?)

quzah

I really like the C++ ignore...oh well. As for the parameter combo:

Code:

scanf("%c*[^\n]*%c", &response );

I never would have thought that one up, thanks.