Output:
Exer6

#include
#include float grade, average, items, sum;
void main(){
clrscr();
average=0;sum=0;do{
printf("Enter grade (-1 to exit): ");
scanf("%f", &grade);
if((grade!=-1)&&(grade<=100)){items++;sum=sum+grade;}} while(grade!=-1); average=sum/items;printf("Class Average: %.2f\n", average); if((average>=95)&&(average<=100)){ printf("Rating: A");} else if((average>=90)&&(average<=94)){printf("Rating: B");} else if((average>=85)&&(average<=89)){printf("Rating: C");} else if((average>=80)&&(average<=84)){printf("Rating: D");} else if((average>=75)&&(average<=79)){printf("Rating: E");} else if(average<=74){printf("Rating: FAILED");} getch(); }