/* write a program that reads a sequence of valid grades (valid is an integer
between 0 and 100 inclusive). The program finds the average B grade, and total average and
number of students in the class  */

#include<stdio.h>
int main(){
	int grade, sum_B=0, count_B=0, count_total=0, sum_total=0;
	double ave_B, ave_total;

	//sentinel controlled repetition
	printf("enter valid grade \n");
	scanf("%d", &grade);
	while(grade>=0 && grade<=100){
		count_total++;
		sum_total+=grade;
		if(grade>=80 && grade<=89){
				sum_B+=grade;
				count_B++;
		}
		scanf("%d", &grade);
	}
	if(count_total>0){
		ave_total=(double)(sum_total)/count_total;
		printf("total average %.2f number of students %d\n",ave_total,count_total);
		if(count_B>0){
			ave_B=(double)(sum_B)/count_B;
			printf("there are %d students got B grade\n",count_B);
			printf("B grade average is %.1f\n",ave_B);
		}
		else
			printf("no B grades\n");
	}
	else
		printf("no students in the class\n");
	return 0;
}