Assigning a value to a structure element that figures as argument in a function

emptytheory

I'm not sure if that title makes sense, but I'll try to explain.

a = [.b = 0]
function c(d)
    d = 1
return void
c(a.b)

After running this function, the value of a.b is still 0. It seems I can't change the value of a.b to 1 by feeding it into a function that changes the value of its argument to 1. Is such a function impossible? Can someone explain why and tell me if there is another way of doing this?

MikeDX

you are passing the value not the refence, you could do a.b = c(a.b)

emptytheory

@MikeDX I'm afraid I don't understand the terminology. What does it mean to pass a reference?

emptytheory

@MikeDX I think I get it now. What goes into the function is the value of a.b, whatever that is.

MikeDX

that's right. you are sending it the value and not the variable

mixaal

But if you declare an array of the structure, I strongly believe you would pass a reference (that's how array is usually implemented). Here is the code I use:

{code}
struct sometype
float elevation
...
endStruct

sometype terrainHeightMap[32][32]

function setup(terrainMap)
for x=0 to 32 loop
for y=0 to 32 loop
terrainMap[x][y].elevation = ... // whatever you want here
repeat
repeat
return void

// Later on:
print(terrainHeightMap[10][10].elevation)
{code}

MikeDX

that is true but he has passed a.b and not just b 👍

mixaal

Yes, exactly, that was my 2 cents on how to assign a value into structure, when needed. Not sure what happens if the whole structure is passed as an argument, if that is a reference or a value. Mu guess is by value ;-). I.e in this what would happen if only a is passed and the function would assign a.b=3