Case 2

#include
#include

void main()
{ clrscr();
float grade, average, sum;
int a=0;

while (grade!=-1)
{ sum= sum + grade;
printf("\n\n");
printf("\n Enter grade; -1 to exit");
scanf("% f", &grade);

if(grade==-1)
{
printf("\n\n\n");
printf("\n\t\t\t Average is %.2f\n", average=sum/a);}
a++;
if(average>=95 && average<=100)
{
printf("\n\n Rated of average:A");
}
{
else if (average>=90 && average: B)
}
else if (average>=89 && average <=90)
{
printf("\n\n Rated of this average:");
}

getch();
}