added function which calculates grades sum with dropped lowest

1 files changed, 50 insertions, 0 deletions

diff --git a/GradeBook_lib.tcl b/GradeBook_lib.tcl
index d189acd..dff6624 100755
--- a/GradeBook_lib.tcl
+++ b/GradeBook_lib.tcl
@@ -203,6 +203,56 @@ proc calculteMaxPointsInCategory { category } {
 	return [list $max_points($category) $col_number_in_category $all_col_in($category)]
 }
 
+proc listSum { l } {
+	set sum 0
+	foreach e $l {
+		set sum [ expr {$e + $sum}]
+	}
+	return $sum
+}
+
+proc dropTheLowestGrades {num_to_drop grades grades_max_possible} {
+	# this procedure drops the grade with the lowest weight i.e. grade/max_grade
+
+	# this is recursively called so 1st to check is exit condition
+	if { $num_to_drop <= 0 } {
+		set grades_sum [listSum $grades]
+		set grades_max_sum [listSum $grades_max_possible]
+		return [list $grades_sum $grades_max_sum]
+	}
+
+	# let's find the index of  grade with the smallest grade/max_possible ratio
+	set sm_ind -1; # non existing
+	set smallest_ratio 10000; # something very big (larger than 1)
+	set i 0
+	foreach  max_val $grades_max_possible {
+		# grades with zero max_possible belong to bonuses
+		# and it is impossible to calculate its weight anyway
+		if { $max_val != 0 } {
+			set grade [lindex $grades $i]
+			set grade_weight [expr {1.0*$grade/$max_val}]
+		} else {
+			# we cannot divide by zero
+			# so we just put something very big (much larger than 1)
+			set grade_weight 1000000; # larger than default smallest_ratio
+		}
+		# update lowest contribution
+		if { $grade_weight < $smallest_ratio } {
+				set sm_ind $i
+				set smallest_ratio $grade_weight
+		}
+		incr i 
+	}	
+	if { $sm_ind >=0 } {
+		# let's remove lowest contribution
+		set grades [lreplace $grades $sm_ind $sm_ind]
+		set grades_max_possible [lreplace $grades_max_possible $sm_ind $sm_ind]
+	}
+	incr num_to_drop -1
+
+	return [dropTheLowestGrades $num_to_drop $grades $grades_max_possible]
+}
+
 proc calculteSumOfPointsForStudentInCategory { student category } {
 	set all_col_in($category) [ findColumnNamesInCategory $category ]
 	set gained_points 0