/* solution-4.c

   demonstrates the following:

   - reading individual characters from stdin
   - converting the ASCII character code of a digit key to it numberic value
   - i.e. converting '5' to 5.
   - the loop models Horner's method of evaluating a polynomial

*/

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


int main(  )
{
	int number=0;

	printf("\nYou will be repeatedly prompted for a single digt key and a RETURN.\n As soon as you enter a non digit character the loop will terminate\n\n");
	do
	{
		char digit; /* declare it in here since its not needed outside */
		printf("> ");
		fflush(stdout);
		scanf("%c", &digit ); /* OR - could have used digit = getc(stdin) */
		getchar(); /* to eat the RETURN from the stdin buffer */
		if (digit < '0' || digit>'9') break; /* OR - could have used isdigit(digit) */
		number *= 10;
		number += digit-'0'; /* digit-'0'  converts character '5' to number 5 */
		printf("number: %d\n",number );
	} while ( 1 ); /* nfinte loop - we must break out */

	printf("\nFinal value of number: %d\n", number );

	return 0;

} /* END MAIN */