#include <stdio.h>

​

// This function returns a letter grade based on the average

char gradeFunction(double avg) {

  if (avg >= 90) return 'A';

  else if (avg >= 80) return 'B';

  else if (avg >= 70) return 'C';

  else if (avg >= 60) return 'D';

  else return 'F';

}

​

int main(void) {

  int count;

  double sum = 0, grade;

​

  // Ask the user to enter total grades between 1 to 5

  printf("How many grades (1 to 5)? ");

  scanf("%d", &count);

​

  // Validate that count is between 1 and 5

  if (count < 1 || count > 5) {

    printf("Invalid number. You must enter between 1 and 5 grades.\n");

    return 1;  // Exit

  }

​

  // Loop to collect each grade

  for (int i = 1; i <= count; i++) {

    printf("Enter grade %d: ", i);

    scanf("%lf", &grade);

    sum += grade;

  }

​

  // Calculate the average score

  double avg = sum / count;

​

  // Display numeric average

  printf("Average: %.2f\n", avg);

​

  // Display letter grade

  printf("Letter grade: %c\n", gradeFunction(avg));

​

  return 0;

}

​