/*Write a program in C to print grade of students*/
//if/else if => grading, if/else => validations, round() => round off

#include<stdio.h>
#include<math.h>
int main ()
{
	int result;
	float m1, m2, m3, resultFloat;
	printf ("\nEnter the marks of three subjects: ");
	scanf ("%f%f%f", &m1, &m2, &m3); 
	if ((m1>100 || m2>100 ||m3>100) || (m1<0 || m2<0 || m3<0)) //validates inputs
		printf ("\nEneter valid marks of each subject (out of 100)");
	else {
		resultFloat = (m1+m2+m3)/3;
		printf("\nThe average of marks entered is %f",resultFloat);
		result = round((m1+m2+m3)/3);
		printf("\nRounding off avg. marks...\nNew avg. marks: %d",result);
		if (result >= 91 && result <=100)
			printf ("\nGrade 'O'");
		else if (result >= 81 && result <=90)
			printf ("\nGrade 'E'");
		else if (result >= 71 && result <=80)
			printf ("\nGrade 'A'");
		else if (result >= 61 && result <=70)
			printf ("\nGrade 'B'");
		else if (result >= 51 && result <=60)
			printf ("\nGrade 'C'");
		else if (result >= 40 && result <=50)
			printf ("\nGrade 'D'");
		else if (result >= 0 && result <40)
			printf ("\nGrade 'F' (Fail)");
		else
			printf ("\nAn error occured while caculation");	
		}
	return 0;
}