Returning an array?

CantSayIHave

I have this code:

int[] colors(String shapeShade){ if(shapeShade == "red"){ int[] colorArray = {255,0,0}; } else if(shapeShade == "blue"){ int[] colorArray = {0,0,255}; } else if(shapeShade == "green"){ int[] colorArray = {0,255,0}; } } return colorArray; }

And it seems it should work, but it keeps telling me "expected EOF", how do I return this array? If it matters, I'm returning this to an array of the same size in the constructor of a class.

GoToLoop

http://forum.processing.org/two/discussion/8045/how-to-format-code-and-text

• Variables are created when we declare their type like: int[] colorArray = {255, 0, 0};.
• However, they exist inside a scope. And those colorArray are created within if scoped blocks.
• So @ return colorArray;, variable colorArray doesn't exist anymore.
• Another tricky bug is comparing String objects via == equality operator.
• Please use equals() instead: https://processing.org/reference/String_equals_.html

GoToLoop

Hmm... seems like you already had problems w/ scoping before: :-\"

http://forum.processing.org/two/discussion/11221/class-not-working-what-am-i-doing-wrong

blindfish

The function is also closed before the return statement: check your {braces}...

I remember being bitten by the issue @GoToLoop refers to. Since colorArray gets declared only inside conditions there's a risk that it never gets declared. So declare the empty variable before the conditions, rather than repeatedly inside them... You could even remove a condition altogether: e.g. set its value to red and then override it when appropriate.

GoToLoop

Since colorArray gets declared only inside conditions there's a risk that it never gets declared.

I don't get what you meant by "risk". Declarations always overshadow other variables declared in outer scopes if they happen to have the same name until the end of the inner scope.

Chrisir

do all { } automatically make a new scope?

like for and if () { } ?

quark

Yes

Chrisir

thanks

blindfish

@GoToLoop: my description wasn't meant to be overly technical, but the way I always thought about this situation was that I may know that one of the three conditions will always return true, so there should be a value to return, but the interpreter can't know this so reports it as an error...

I guess on a technical level it simply can't find the variable declared in the same scope?

GoToLoop

... my description wasn't meant to be overly technical,

• Sorry about that! I was over worried that it could be misinterpreted by the OP. 8-|
• Of course the very 1st bug is simply an extra too early closing } curly brace.
• But that's easily spottable by hitting CTRL+T in the PDE... :-\"
• Right after that is the "inexisting" colorArray variable when code reaches the return statement.
• And finally the insidious bug of comparing String via == operator.
• However, that is just a potential bug in case the String reference passed doesn't come from a literal "" 1, like "red", "blue" or "green". :P

GoToLoop

... like for () and if () { }?

Be aware that any declaration inside for's parens is also its own separate scope,
apart from its {}'s scope.
For example, the following code won't compile due the "inexistence" of variable step,
since it doesn't exist inside for () parens's scope: :-B

for (int i = 0; i != 10; i += step) {
  int step = i*2 + 4;
}

CantSayIHave

So if I declare the array like

int[] colorArray = new int[3];

then can I assign data later using

colorArray = {255,0,0};

GoToLoop

The answer is: "Yes & No"! @-)

• Variables can only store 1 value at a single time.
• So when we use the = assign operator, the old stored value is discarded.
• Therefore, it doesn't matter if we assign some array reference early on as in:
  int[] colorArray = new int[3];
• Or simply leave it blank w/o some assignment as in: int[] colorArray;
• Since it's gonna receive a brand new int[] array assignment down the road after all.
• Now the reason I've also said "No"... ^#(^
• The simplified array instantiation w/ just curly braces as in: { 255, 0, 0 }
• is only valid when we're also declaring the variable at the same time as in:
  int[] colorArray = { 255, 0, 0 };
• Otherwise for later reassignments, we are obliged to specify its type before the curly braces:
  colorArray = new int[] { 255, 0, 0 };

P.S.: Processing got a pseudo type called color which is the same as int. ;;)
https://processing.org/reference/color_datatype.html