avg.c

/** avg.c 
  * Author: Marco Cirillo
  * Uses getchar() to compute an average of a series of digits
  */
#include <stdio.h>
int main(int argc, char* argv[]) {
    int total=0,subtotal=0,n=0;
	int c;
	printf("Enter numbers followed by spaces and press enter when finished: ");
	while (c = getchar()) {
		if (isdigit(c)) {
		// The char is not a letter, add to running subtotal
			subtotal *= 10;
			subtotal += c - '0';
		} else if (isspace(c)) {
		// add the subtotal to the total, and increment count of given numbers
			total += subtotal;
			subtotal = 0;
			n++;
			if (c == '\n') break;
		} 
	}
	printf("Average: %.2f\n", (float) (total/n));
	return 0;
}