# include <stdio.h>

int main ( )
{
  float average;
  int count[5];
  int g;
  int grade[100];
  int i;
  char letter;
  int max;
  int min;
  int n;
  int sum;
//
//  Read grades one by one.
//  We can't accept more than 100 grades.
//  If the user enters a "-1", we stop reading grades.
//
  n = 0;
  printf ( "Enter grades one at a time, or -1 when done\n" );

  while ( n < 100 )
  {
    scanf ( "%i", &g );

    if ( g == -1 )
    {
      break;
    }

    grade[n] = g;
    n = n + 1;
  }
  printf ( "%d grades were entered.\n", n );

  if ( n == 0 )
  {
    return 1;
  }
//
//  Compute the average.
//
  sum = 0.0;
  for ( i = 0; i < n; i++ )
  {
    sum = sum + grade[i];
  }
  average = ( float ) sum / ( float ) n;
  printf ( "The average grade was %3.1f\n", average );
//
//  Compute the minimum and maximum.
//
  max = grade[0];
  min = grade[0];
  for ( i = 1; i < n; i++ )
  {
    if ( grade[i] < min )
    {
      min = grade[i];
    }
    if ( max < grade[i] )
    {
      max = grade[i];
    }
  }
  printf ( "The maximum grade was %d\n", max );
  printf ( "The minimum grade was %d\n", min );
//
//  Make a histogram for F/D/C/B/A in count 0/1/2/3/4.
//
  for ( i = 0; i < n; i++ )
  {
    if ( grade[i] < 60 )
    {
      count[0] = count[0] + 1;
    }
    else if ( grade[i] < 70 )
    {
      count[1] = count[1] + 1;
    }
    else if ( grade[i] < 80 )
    {
      count[2] = count[2] + 1;
    }
    else if ( grade[i] < 90 )
    {
      count[3] = count[3] + 1;
    }    
    else
    {
      count[4] = count[4] + 1;
    }  
  }
//
//  Print the histogram:
//
  letter = 'F';
  for ( i = 0; i < 5; i++ )
  {
    printf ( "%c:  %2d\n", letter, count[i] );
    letter = letter - 1;
    if ( letter == 'E' )
    {
      letter = 'D';
    }
  }

  return 0;
}