Nested Control Structures

DO loops, FOR loops, IF statements, GOTO statements are the different control structures which may all be mixed together into one program. Please, see the example below as a demonstration of this mix:

00010 ! This program calculates the average score 00020 print newpage 00030 let sum_of_scores = 0 ! provided for clarity, not required 00040 let average = 0 ! provided for clarity, not required 00050 let number_of_scores = 0 ! provided for clarity, not required 00060 let new_score = 0 ! provided for clarity, not required 00070 start: ! 00080 let more_scores$ = "Y" 00090 do while trim$(uprc$(more_scores$)) = "Y" 00100 print "Do you want to add more scores?" 00110 input more_scores$ 00120 if trim$(uprc$(more_scores$))="N" then 00130 exit do 00140 else if trim$(uprc$(more_scores$))<>"Y" then 00150 print "Invalid entry" 00160 let more_scores$ = "Y" 00170 else 00180 print "How many scores do you want to add?" 00190 input scores_to_add 00200 for count = 1 to scores_to_add 00210 print "Enter new score" 00220 input new_score 00230 if new_score < 0 or new_score > 100 then 00240 print "Invalid score. you will be asked to re-enter the score" 00250 let count -= 1 00260 else 00270 let sum_of_scores += new_score 00280 let number_of_scores += 1 00290 end if 00300 next count 00310 end if 00320 loop 00330 if number_of_scores <> 0 then 00340 let average = sum_of_scores / number_of_scores 00350 print "The average of "&str$(number_of_scores)&" scores is "&str$(average) 00360 print "Do you want to add more scores?" 00370 input more_scores$ 00380 if trim$(uprc$(more_scores$)) = "Y" then 00390 goto start 00400 end if 00410 end if 00420 print "Good bye" 00430 stop