just recustion

[Unreal_Origin]

the is recusion it is in my paint program

code:

var mx, my, mb : int var originalcolour : int var thecolour : int := 4 proc fillingin (x, y, originalcolour, thecolour : int)     drawdot (x, y, thecolour)     if whatdotcolor (x + 1, y) = originalcolour then         fillingin (x + 1, y, originalcolour, thecolour)     end if     if whatdotcolor (x, y + 1) = originalcolour then         fillingin (x, y + 1, originalcolour, thecolour)     end if         if whatdotcolor (x, y - 1) = originalcolour then         fillingin (x, y - 1, originalcolour, thecolour)     end if         if whatdotcolor (x-1, y ) = originalcolour then         fillingin (x-1, y  , originalcolour, thecolour)     end if end fillingin drawoval (255, 255,100, 100,  7) drawbox (0,0,maxx,maxy,7) loop     mousewhere (mx, my, mb)     if mb = 1 then         originalcolour := whatdotcolor (mx, my)         fillingin (mx, my, originalcolour, thecolour)     end if end loop

here is the problem i think it is with turing though, it is that it "stake overflow" but w/e (note this happens when you click to fast before it is done)

[wtd]

The key to recursion is providing a way for your function/procedure to escape the recursion. At least one branch of that if...elsif...else statement has to do something other than call the function/procedure.

[Andy]

nah wtd.. it works.. when it finishes drawing, it'll stop cuz every where it checks will return the right color

[wtd]

No, it really doesn't. It just keeps running and running, until it overflows the stack. Try inserting some code after the code originally posted. The circle will get drawn, and then nothing else will happen, because that procedure is still running.

Every recursive function or procedure has to have a way out.

Consider a basic (very quickly written) factorial function:

code:

function factorial (n : int) : int     if n <= 1 then         result 1     else         result n * factorial (n - 1)     end if end factorial put factorial (4)

You'll notice that there's a very clear exit point. If "n" is less than or equal to 1, the function returns 1. Eventually, it'll get to this point and the function won't call itself.

[zylum]

if you read his code you can see that the procedure does termiate. the function will not be called every time since the four if statements will not be satisfied everytime. and since it's a procedure, it does not need ot return a value. to prove this, exit the final loop after the function call in the if statement which checks for mousedown:

code:

var mx, my, mb : int var originalcolour : int var thecolour : int := 4 proc fillingin (x, y, originalcolour, thecolour : int)     drawdot (x, y, thecolour)     if whatdotcolor (x + 1, y) = originalcolour then         fillingin (x + 1, y, originalcolour, thecolour)     end if     if whatdotcolor (x, y + 1) = originalcolour then         fillingin (x, y + 1, originalcolour, thecolour)     end if     if whatdotcolor (x, y - 1) = originalcolour then         fillingin (x, y - 1, originalcolour, thecolour)     end if     if whatdotcolor (x - 1, y) = originalcolour then         fillingin (x - 1, y, originalcolour, thecolour)     end if end fillingin drawoval (255, 255, 100, 100, 7) drawbox (0, 0, maxx, maxy, 7) loop     mousewhere (mx, my, mb)     if mb = 1 then         originalcolour := whatdotcolor (mx, my)         fillingin (mx, my, originalcolour, thecolour)         exit     end if end loop put "it terminates"

[bugzpodder]

your function is fine as long as originalcolour and thecolour are different. when they are the same, you'll get into an infinite loop and cause stack overflow

[wtd]

Ah. His use of several if statements so close together made my brain think of a chain of if...elsif...else. I was under the impression at least one of those eventualities would happen.

[Andy]

lol its ok wtd.. we still respect you lol even if u suck :p jk