#include <stdio.h>

int main()
{
	float average, score_amount, i, score_total;

	score_amount = 0;
	score_total = 0;

	printf("The program calculates the average of scores you enter.\n");
	printf("End with a negative integer.\n");

	do
	{
	  printf("Enter score (4-10):");
	  scanf("%f", &i);

	  score_total = score_total + i;
	  score_amount = score_amount + 1;


	  if(i < 0)
	  {
	    score_amount = score_amount -1;
		score_total = score_total - i;
		average = score_total / score_amount;
		printf("You entered %.0f scores.\n", score_amount);
		printf("Average score: %.2f", average);
	  }
	}
    while(i >= 0);


return 0;
}