#include?<stdio.h>
int?main()
{
int?count?=?0;
float?num,sum?=?0.0;
printf("Enter?grades:\n");
while(1)
{
scanf("%f",&num);
if(?num?<?0?)
break;
count?++;
sum+=?num;
}
if(?n?>?0)
printf("Grade?average?is?:?%5.2f\n",?sum?/?count);
else
printf("No?grades?inputed.\n");
return?0;
}