/* Negative nested if logic from bottom of condition_action table */
/*Given grades of 4 tests. Get A if average is 90 or above*/
/*B if average is 80-89, C if average is 70-79, D if average is 60-69*/
/*F if average is lower than 60*/

#include <stdio.h>

float test1, test2, test3, test4, average;
char grade;

void main() {
  printf("Type 4 test scores\n");
  scanf ("%f%f%f%f", &test1, &test2, &test3, &test4);
  average = (test1+test2+test3+test4)/4;
  if (average>=60.0)
    if (average>=70.0)
      if (average>=80.0)
	if (average>=90.0)
	  grade = 'A';
	else
	  grade = 'B';
      else
	grade = 'C';
    else
      grade = 'D';
  else
    grade = 'F';
  printf ("%c\n", grade);
}