Array subscripts

[Clayton]

right now i am working on a game (see my post in [Turing Source Code]) and im having a problem with getting rid of any balls that have been clicked on. I am using classes and i have an array of my type "bouncy", in it is the instance field (pointer to my ball class) and a point_taken field (dont worry about it), basically what i am trying to do is have a ball disappear when a ball is clicked, then free the pointer reference to that object, thus saving memory (as i dont need that ball anymore), then resize my array to one less element (having pushed the ball to be "deleted" to the upper bounds of the array) then carry on with the rest of the program, however i am having trouble in my "delete_ball" procedure, i get the error "Array subscript is out of range" when i try to "push" the ball to be deleted to the upper bounds of the array. I dont know why i am getting this error, and it would be appreciated if you guys could look at my code and see if you can figure out why its happening, thx in advance for your help

Turing:

type bouncy :     record         instance : ^balls         points_taken : boolean     end record var ball : flexible array 1 .. 0 of bouncy procedure delete_ball (object_to_be_deleted : int)     var temp : bouncy     for lp : object_to_be_deleted .. upper (ball)         temp := ball (lp)         %-------ERROR-------%         ball (lp) := ball (lp + 1)         %-------ARRAY SUBSCRIPT IS OUT OF RANGE-------%         ball (lp + 1) := temp     end for     free balls, ball (upper (ball)).instance     new ball, upper (ball) - 1 end delete_ball %down here in my main loop i run a check to see if the ball is clicked, if it %is i run this proc, but i keep getting that error...

[Cervantes]

'lp' reaches a max value of `upper (ball)'. So `lp +1', which is the subscript in the line producing the error, ranges to `upper (ball) + 1', which is out of range of the array.

Solution: modify the range of your for loop to only reach `upper (ball) - 1'.

[Clayton]

aha thank you very much Cervantes, that was a bit of an oopsie on my part, i thought i had put upper(ball)-1 oh well

[Clayton]

ok now im having another problem, the delete_ball proc is working fine, however, after you click two or three balls (sometimes even the first) Turing crashes with an Array subscript is out of range error, here is my code so far :

code:

class balls     import Draw, Mouse     export initialize, move, draw, draw_     var size, x, y, colur : int     var x_vel, y_vel : int     var draw_ : boolean := true     proc initialize (x_, y_, size_, color_, xVel, yVel : int)         x := x_         y := y_         size := size_         x_vel := xVel         y_vel := yVel         if color_ >= 1 and color_ <= maxcolor then             colur := color_         else             colur := brightred         end if     end initialize     proc move         x += x_vel         y += y_vel         if x + size >= maxx then             x := maxx - size             x_vel *= -1         end if         if x - size <= 0 then             x := size             x_vel *= -1         end if         if y + size >= maxy then             y := maxy - size             y_vel *= -1         end if         if y - size <= 0 then             y := size             y_vel *= -1         end if     end move     function check_clicked : boolean         %check to see if any of the ball have been clicked         var mx, my, mb : int         Mouse.ButtonChoose ("multibutton")         if Mouse.ButtonMoved ("updown") then             Mouse.Where (mx, my, mb)             if mx > x - size and mx < x + size and my > y - size and my < y + size and mb >= 1 then                 result true             end if         end if         result false     end check_clicked     proc draw         if check_clicked then             draw_ := false         end if         if draw_ then             Draw.FillOval (x, y, size, size, colur)         end if     end draw end balls %----------------------------------------------------------------------------------------------- View.Set ("offscreenonly,graphics") type bouncy :     record         instance : ^balls         points_taken : boolean     end record var ball : flexible array 1 .. 0 of bouncy var mouse_x, mouse_y, mouse_buttons : int var points, ball_amount : int := 0 var keys : array char of boolean const ball_color : int := brightred const min_size : int := 10 const max_size : int := 20 const timer : int := 60000 %60 seconds (60 * 1000 ;) ) var tim : int := Time.Elapsed var tim2 : int := Time.Elapsed - timer %---------------------------------------------------------------------------------------------- procedure lose     var font : int := Font.New ("times new roman:20:bold")     Draw.Cls     Font.Draw ("You Lose!!", maxx div 2 - 100, maxy - 25, font, brightred)     locatexy (maxx div 2 - 100, maxy - 50)     put "You created ", upper (ball), " balls, however you had ", ball_amount, " ball(s) left" end lose procedure win     var font : int := Font.New ("times new roman:20:bold")     Draw.Cls     Font.Draw ("You Win!!", maxx div 2 - 150, maxy - 25, font, brightblue)     locatexy (maxx div 2 - 150, maxy - 50)     put "You created ", upper (ball), " balls and clicked all of them in 60 seconds"     locatexy (maxx div 2 - 150, maxy - 75)     put "giving you a score of ", points, " points, Congratulations." end win procedure delete_ball (object_to_be_deleted : int)     var temp : bouncy     for lp : object_to_be_deleted .. upper (ball) - 1         temp := ball (lp)         ball (lp) := ball (lp + 1)         ball (lp + 1) := temp     end for     free balls, ball (upper (ball)).instance     new ball, upper (ball) - 1 end delete_ball procedure new_ball (x, y, size, colur : int)     new ball, upper (ball) + 1     new balls, ball (upper (ball)).instance     ball (upper (ball)).points_taken := false     ball (upper (ball)).instance -> initialize (x, y, size, colur, Rand.Int (1, 7), Rand.Int (1, 7))     ball_amount += 1 end new_ball %----------------------------------------------------------------------------------------------- %Main Program new_ball (maxx div 2, maxy div 2, 20, ball_color) loop     Draw.Cls     Mouse.Where (mouse_x, mouse_y, mouse_buttons)     tim2 := Time.Elapsed - timer     put "Balls: ", ball_amount, "                 Points: ", points, "                 Time: ", round ((tim - tim2) / 1000)     put upper (ball)     Input.KeyDown (keys)     %create more balls by holding down the enter key     if keys (KEY_ENTER) then         new_ball (Rand.Int (max_size, maxx - max_size), Rand.Int (max_size, maxy - max_size), Rand.Int (min_size, max_size), ball_color)         Input.Flush     end if     Time.DelaySinceLast (30)     for i : 1 .. upper (ball)         %move and draw the ball         ball (i).instance -> move         ball (i).instance -> draw     end for     for j : 1 .. upper (ball)         %the if not ball (j).instance -> draw_ is if the balls have been drawn and clicked on         %-------ERROR-------%         if not ball (j).instance -> draw_ and not ball (j).points_taken then             %-------ARRAY SUBSCRIPT IS OUT OF RANGE-------%             %do this to stop points to keep being gained every iteration of the loop             ball (j).points_taken := true             ball_amount -= 1             delete_ball (j)             points += 10         end if     end for     %timer     exit when tim - tim2 <= 0     View.Update end loop if ball_amount >= 1 then     lose else     win end if

i have no idea why this is happening, any help would be appreciated

[Cervantes]

You deleted a ball from the array, so now the array has one less element. But the range doesn't change.

Let's say your array was from 1 .. 5. You delete an element, so it is now 1 .. 4. But the for loop doens't re-evaluate `upper (ball)', so it is still going 1..5. Hence the error.

You may wish to read this for some ideas.

[Clayton]

thank you very much Cervantes, if you werent a mod id give you bits, but...

anyways on to my next question, this is my current code so far:

code:

class balls     import Draw, Mouse     export initialize, move, draw, draw_     var size, x, y, colur : int     var x_vel, y_vel : int     var draw_ : boolean := true     proc initialize (x_, y_, size_, color_, xVel, yVel : int)         x := x_         y := y_         size := size_         x_vel := xVel         y_vel := yVel         if color_ >= 1 and color_ <= maxcolor then             colur := color_         else             colur := brightred         end if     end initialize     proc move         x += x_vel         y += y_vel         if x + size >= maxx then             x := maxx - size             x_vel *= -1         end if         if x - size <= 0 then             x := size             x_vel *= -1         end if         if y + size >= maxy then             y := maxy - size             y_vel *= -1         end if         if y - size <= 0 then             y := size             y_vel *= -1         end if     end move     function check_clicked : boolean         %check to see if any of the ball have been clicked         var mx, my, mb : int         Mouse.ButtonChoose ("multibutton")         if Mouse.ButtonMoved ("updown") then             Mouse.Where (mx, my, mb)             if mx > x - size and mx < x + size and my > y - size and my < y + size and mb >= 1 then                 result true             end if         end if         result false     end check_clicked     proc draw         if check_clicked then             draw_ := false         end if         if draw_ then             Draw.FillOval (x, y, size, size, colur)         end if     end draw end balls %----------------------------------------------------------------------------------------------- View.Set ("offscreenonly,graphics") type bouncy :     record         instance : ^balls         points_taken : boolean     end record var ball : flexible array 1 .. 0 of bouncy var elements_to_be_removed : flexible array 1 .. 0 of int var mouse_x, mouse_y, mouse_buttons : int var points, ball_amount : int := 0 var keys : array char of boolean const ball_color : int := brightblue const min_size : int := 10 const max_size : int := 20 const timer : int := 60000 %60 seconds (60 * 1000 ;) ) var tim : int := Time.Elapsed var tim2 : int := Time.Elapsed - timer %---------------------------------------------------------------------------------------------- procedure lose     var font : int := Font.New ("times new roman:20:bold")     Draw.Cls     Font.Draw ("You Lose!!", maxx div 2 - 100, maxy - 25, font, brightred)     locatexy (maxx div 2 - 100, maxy - 50)     put "You created ", upper (ball), " balls, however you had ", ball_amount, " ball(s) left" end lose procedure win     var font : int := Font.New ("times new roman:20:bold")     Draw.Cls     Font.Draw ("You Win!!", maxx div 2 - 150, maxy - 25, font, brightblue)     locatexy (maxx div 2 - 150, maxy - 50)     put "You created ", upper (ball), " balls and clicked all of them in 60 seconds"     locatexy (maxx div 2 - 150, maxy - 75)     put "giving you a score of ", points, " points, Congratulations." end win procedure delete_ball (object_to_be_deleted : int)     var temp : bouncy     for lp : object_to_be_deleted .. upper (ball) - 1         temp := ball (lp)         ball (lp) := ball (lp + 1)         ball (lp + 1) := temp     end for     free balls, ball (upper (ball)).instance     new ball, upper (ball) - 1 end delete_ball procedure new_ball (x, y, size, colur : int)     new ball, upper (ball) + 1     new balls, ball (upper (ball)).instance     ball (upper (ball)).points_taken := false     ball (upper (ball)).instance -> initialize (x, y, size, colur, Rand.Int (1, 7), Rand.Int (1, 7))     ball_amount += 1 end new_ball %----------------------------------------------------------------------------------------------- %Main Program new_ball (maxx div 2, maxy div 2, 20, ball_color) loop     Draw.Cls     Mouse.Where (mouse_x, mouse_y, mouse_buttons)     tim2 := Time.Elapsed - timer     put "Balls: ", upper (ball), "                 Points: ", points, "                 Time: ", round ((tim - tim2) / 1000)     Input.KeyDown (keys)     %create more balls by holding down the enter key     if keys (KEY_ENTER) then         new_ball (Rand.Int (max_size, maxx - max_size), Rand.Int (max_size, maxy - max_size), Rand.Int (min_size, max_size), ball_color)         ball_amount += 1         Input.Flush     end if     Time.DelaySinceLast (30)     for i : 1 .. upper (ball)         %move and draw the ball         ball (i).instance -> move         ball (i).instance -> draw     end for     new elements_to_be_removed, 0 %start an empty array     for j : 1 .. upper (ball)         %the if not ball (j).instance -> draw_ is if the balls have been drawn and clicked on         if not ball (j).instance -> draw_ and not ball (j).points_taken then             %do this to stop points to keep being gained every iteration of the loop             ball (j).points_taken := true             %used for the delete_ball procedure because it screws up if i have delete_ball(j) in here             new elements_to_be_removed, upper (elements_to_be_removed) + 1             elements_to_be_removed (upper (elements_to_be_removed)) := j %removes ball j in next for loop             points += 10         end if     end for     for i : 1 .. upper (elements_to_be_removed)         delete_ball (elements_to_be_removed (i))     end for     %timer     exit when tim - tim2 <= 0     View.Update end loop if ball_amount >= 1 then     lose else     win end if

now if you run that, and create a whole bunch of balls (using the enter key), you will notice that you dont have to just click on a ball, you can just hold down the button and move the mouse around and you can "click" on all of the balls, i would like to know how to fix this, i have so far tried using a combination of Mouse.ButtonMoved and Mouse.ButtonChoose but it isnt working, any help would be appreciated

[Cervantes]

Just use a variable to keep track of the mouse buttons previous state.

So if the previous state says it the mouse button was up, and the current state says the mouse button is down, then you know the mouse was just clicked, and you should register that, removing a ball under the mouse if there is one.

On the other hand, if the previous state says the mouse button was down, and the current state says the mouse button is down, then the mouse is being held down, and this should not be registered as a click.

[Clayton]

so have something like this?

code:

var button, oldbutton :int := 0 var x,y:int Mouse.Where (x,y,button) if button = 1 and oldbutton = 0 then     oldbutton = 1     %do stuff elsif button = 0 and oldbutton = 1 then     oldbutton := 0 end if

[Clayton]

okay i got that to work, kinda. for some strange reason, doing it this way, you can only click and clear a ball in the order they appeared on the screen, i dont know why this is happening, but i think it has something to do with the way im calling my check_clicked procedure now, heres my up to date code:

code:

class balls     import Draw, Mouse     export initialize, move, draw, draw_, check_clicked     var size, x, y, colur : int     var x_vel, y_vel : int     var draw_ : boolean := true     proc initialize (x_, y_, size_, color_, xVel, yVel : int)         x := x_         y := y_         size := size_         x_vel := xVel         y_vel := yVel         if color_ >= 1 and color_ <= maxcolor then             colur := color_         else             colur := brightred         end if     end initialize     proc move         x += x_vel         y += y_vel         if x + size >= maxx then             x := maxx - size             x_vel *= -1         end if         if x - size <= 0 then             x := size             x_vel *= -1         end if         if y + size >= maxy then             y := maxy - size             y_vel *= -1         end if         if y - size <= 0 then             y := size             y_vel *= -1         end if     end move     procedure check_clicked (mx, my, mb : int)         %check to see if the ball has been clicked         if mx > x - size and mx < x + size and my > y - size and my < y + size and mb >= 1 then             draw_ := false         else             draw_ := true         end if     end check_clicked     proc draw         if draw_ then             Draw.FillOval (x, y, size, size, colur)         end if     end draw end balls %----------------------------------------------------------------------------------------------- View.Set ("offscreenonly,graphics") type bouncy :     record         instance : ^balls         points_taken : boolean     end record var ball : flexible array 1 .. 0 of bouncy var elements_to_be_removed : flexible array 1 .. 0 of int var mouse_x, mouse_y, mouse_buttons, oldbutton : int := 0 var points, ball_amount : int := 0 var keys : array char of boolean const ball_color : int := brightblue const min_size : int := 10 const max_size : int := 20 const timer : int := 60000 %60 seconds (60 * 1000 ;) ) var tim : int := Time.Elapsed var tim2 : int := Time.Elapsed - timer %---------------------------------------------------------------------------------------------- procedure lose     var font : int := Font.New ("times new roman:20:bold")     Draw.Cls     Font.Draw ("You Lose!!", maxx div 2 - 100, maxy - 25, font, brightred)     locatexy (maxx div 2 - 100, maxy - 50)     put "You created ", ball_amount, " balls, however you had ", upper (ball), " ball(s) left" end lose procedure win     var font : int := Font.New ("times new roman:20:bold")     Draw.Cls     Font.Draw ("You Win!!", maxx div 2 - 150, maxy - 25, font, brightblue)     locatexy (maxx div 2 - 150, maxy - 50)     put "You created ", ball_amount, " balls and clicked all of them in 60 seconds"     locatexy (maxx div 2 - 150, maxy - 75)     put "giving you a score of ", points, " points, Congratulations." end win procedure check_click (instance : int)     if mouse_buttons = 1 and oldbutton = 0 then         oldbutton := 1         ball (instance).instance -> check_clicked (mouse_x, mouse_y, mouse_buttons)     elsif mouse_buttons = 0 and oldbutton = 1 then         oldbutton := 0     end if end check_click procedure delete_ball (object_to_be_deleted : int)     var temp : bouncy     for lp : object_to_be_deleted .. upper (ball) - 1         temp := ball (lp)         ball (lp) := ball (lp + 1)         ball (lp + 1) := temp     end for     free balls, ball (upper (ball)).instance     new ball, upper (ball) - 1 end delete_ball procedure new_ball (x, y, size, colur : int)     new ball, upper (ball) + 1     new balls, ball (upper (ball)).instance     ball (upper (ball)).points_taken := false     ball (upper (ball)).instance -> initialize (x, y, size, colur, Rand.Int (1, 7), Rand.Int (1, 7))     ball_amount += 1 end new_ball %----------------------------------------------------------------------------------------------- %Main Program new_ball (maxx div 2, maxy div 2, 20, ball_color) loop     Draw.Cls     tim2 := Time.Elapsed - timer     put "Balls: ", upper (ball), "                 Points: ", points, "                 Time: ", round ((tim - tim2) / 1000)     put "Button: ", mouse_buttons, "        Old Button: ", oldbutton     Input.KeyDown (keys)     %create more balls by holding down the enter key     if keys (KEY_ENTER) then         new_ball (Rand.Int (max_size, maxx - max_size), Rand.Int (max_size, maxy - max_size), Rand.Int (min_size, max_size), ball_color)         Input.Flush     end if     Time.DelaySinceLast (30)     for i : 1 .. upper (ball)         %move and draw the ball         Mouse.Where (mouse_x, mouse_y, mouse_buttons)         check_click (i)         ball (i).instance -> move         ball (i).instance -> draw     end for     new elements_to_be_removed, 0     %start an empty array     for j : 1 .. upper (ball)         %the if not ball (j).instance -> draw_ is if the balls have been drawn and clicked on         if not ball (j).instance -> draw_ and not ball (j).points_taken then             %do this to stop points to keep being gained every iteration of the loop             ball (j).points_taken := true             %used for the delete_ball procedure because it screws up if i have delete_ball(j) in here             new elements_to_be_removed, upper (elements_to_be_removed) + 1             elements_to_be_removed (upper (elements_to_be_removed)) := j     %removes ball j in next for loop             points += 10         end if     end for     for i : 1 .. upper (elements_to_be_removed)         delete_ball (elements_to_be_removed (i))     end for     %timer     exit when tim - tim2 <= 0     View.Update end loop if upper (ball) >= 1 then     lose else     win end if

any help would be appreciated

[TheOneTrueGod]

I believe it is because of this:

code:

if mouse_buttons = 1 and oldbutton = 0 then         oldbutton := 1         ball (instance).instance -> check_clicked (mouse_x, mouse_y, mouse_buttons)     elsif mouse_buttons = 0 and oldbutton = 1 then         oldbutton := 0     end if

If you click on ball(2), it checks ball 1, sets oldbutton to 1, realises you havn't clicked on ball 1, then moves on. Now it checks ball 2, but oldbutton = 1 and button = 1, so nothing happens.

What I normally do is:

code:

%Pseudocode loop    oldbutton := button    mousewhere(mx,my,button)    %Do stuff, but never change button or oldbutton variables    View.Update    delay    cls end loop

Also, You have a lot of global-ish variables there -- You should consider trying to eliminate them, and have the procedures run purely on parameters (Actually, for the "Clicked On" procedures, these should be functions that return booleans )

[TheOneTrueGod]

Sorry for the double post, but I just came across this post by you in the application section, and thought it fit perfectly here as a message to you

Superfreak wrote:

i noticed in your code you are using randint, i ask you : why? randint is a procedure that changes the value of your variable, why not use Rand.Int, a function? generally speaking, when you have a choice between a function or a procedure to do something, take the function

[Ultrahex]

Just To Notify You, if you check here first i have supplied you with i think all the information your going to need i accidently posted in the turing source code area oh well
anyhow
http://www.compsci.ca/v2/viewtopic.php?t=13292
thats link to your post over there and my info is there with examples and all!

peace

[Clayton]

well actually if you look at the originaly code the check_clicked procedure in my balls class was originally a fcn, however, when i added in the button,oldbutton variables to control clicking, i couldnt figure out immediately how to use it with a function without changing the draw_ variable from within the class outside of the class (a very, very bad practice ) so ive temporarily made it a procedure for now.

as for my problem i figured it out, it was pretty much like you said TOTG, i played with it a bit and got it to work, my check_click procedure looks like this now (outside of the class):

code:

procedure check_click     Mouse.Where (mouse_x, mouse_y, mouse_buttons)     if mouse_buttons = 1 and oldbutton = 0 then         for i : 1 .. upper (ball)             oldbutton := 1             ball (i).instance -> check_clicked (mouse_x, mouse_y, mouse_buttons)         end for     elsif mouse_buttons = 0 and oldbutton = 1 then         oldbutton := 0     end if end check_click

and it works fine right now (even if it isnt the prettiest )

[NikG]

SuperFreak82 wrote:

code:

procedure check_click     Mouse.Where (mouse_x, mouse_y, mouse_buttons)     if mouse_buttons = 1 and oldbutton = 0 then         for i : 1 .. upper (ball)             oldbutton := 1             ball (i).instance -> check_clicked (mouse_x, mouse_y, mouse_buttons)         end for     elsif mouse_buttons = 0 and oldbutton = 1 then         oldbutton := 0     end if end check_click

and it works fine right now (even if it isnt the prettiest )

It may work, but it's not as easy to understand. Do what Cervantes, TOTG, and even I have recommended in your other post:

code:

procedure check_click     oldbutton := mouse_buttons     Mouse.Where (mouse_x, mouse_y, mouse_buttons)     if mouse_buttons = 1 and oldbutton = 0 then         for i : 1 .. upper (ball)             ball (i).instance -> check_clicked (mouse_x, mouse_y, mouse_buttons)         end for     end if end check_click

[Clayton]

whats so hard to understand about mine? the way i see it mine is actually easier to understand because what is happening is more apparent