UNIX for Beginners Questions & Answers

Billy     Final           Final     82     100
Billy     Survey        WS       5       5
Bob     Homework   H01      19     100
Bob     Homework   H02      82     100
 Sam    Quiz            Q01      95     100

#!/usr/bin/perl
   
  open ($input, '<', $ARGV[0]);
   
  $header=<$input>;   
   
  $i =0;
   
  %data = ();
   
  @names;
   
  while ($line = <$input>)
  {
      
      chomp $line;
    
      @field = split "," , $line;
    
      $names[$i] = $field[0];
   
      push (@{$data{$names[$i]}}, ($field[3], $field[4]));
    
      $i = $i + 1;
  }
   
  close $input;
   
  printf("%-8s %8s \t %s \n", "Name", "Percent", "Letter");
   
  foreach $key ( sort keys %data )
  {
     
      @value = @{$data{$key}};
   
      $total = 0;
    
      $possible = 0;
    
      $percent = 0;
    
      $i = 0;
    
      foreach $val (@value)
      {
          if($i % 2 == 0)
          {
              $total += $val;
          }
          
          else
          {
              $possible += $val;
          }
       
              $i += 1;
      
      }
  

  foreach $_ (keys %names) {
      $Homework=($total[$_ . "Homework"] / $possible[$_ . "Homework"]) * 0.10;
      $Lab =($total[$_ . "Lab"] / $possible[$_ . "Lab"]) * .30;
      $Final = ($total[$_ . "Final"] / $possible[$_ . "Final"]) * .15;
      $Quiz = ($total[$_ . "Quiz"] / $possible[$_ . "Quiz"]) * .40;
      $Survery = ($total[$_ . "Survey"] / $possible[$_ . "Survey"]) * .05;
      $percent = ($Homework + $Lab + $Final + $Quiz + $Survery) * 100;
   
      printf "%s\t%.2f\t", $_, $percent;
      if ($percent >= 90 && $percent <= 100) {
      print 'A';
      }
      elsif ($percent >= 80 && $percent < 90) {
      print 'B';
      }
      elsif ($percent >= 70 && $percent < 80) {
      print 'C';
      }
      elsif ($percent >= 60 && $percent < 70) {
      print 'D';
      }
      else {
      print 'E';
      }
      printf("%-8s %8.2f \t %4s\n", $key, $percent, $grade);
  }
  }

foreach $_ (keys %names) {
      $Homework=($total[$_ . "Homework"] / $possible[$_ . "Homework"]) * 0.10;
      $Lab =($total[$_ . "Lab"] / $possible[$_ .[$_ . "Lab"]) * .30;
      $Final = ($total[$_ . "Final"] / $possible[$_ . "Final"]) * .15;
      $Quiz = ($total[$_ . "Quiz"] / $possible[$_ . "Quiz"]) * .40;
      $Survery = ($total[$_ . "Survey"] / $possible[$_ . "Survey"]) * .05;
      $percent = ($Homework + $Lab + $Final + $Quiz + $Survery) * 100;