Objective C method syntax clarification

Question

I'm new to Objective C and I'm going through a tutorial I found online. The tutorial starts to talk about messaging and argument separation and gives an example:

When there's more than one argument, they're declared within the method name after the colons. Arguments break the name apart in the declaration, just as in a message.
- (void)setWidth:(float)width: height:(float)height; 

I don't think there is suppose to be a colon after width, but I could be wrong. From what I've researched, I believe that it's a typo, but since I am new I just wanted to check.

Is the method just setWidth: height: ? Or is there another argument after the (float)width other than height:(float)height?

pwc · Accepted Answer · 2011-02-07 06:50:22Z

It's a typo. The method signature should read:

- (void)setWidth:(float)width height:(float)height;

The method name is setWidth:height: and you would call it like this:

[someObject setWidth:aFloat height:anotherFloat];

Moshe · Accepted Answer · 2011-02-07 06:47:38Z

You are correct. The middle colon seems to be a typo. After a colon, there should be a variable placeholder. If there's a space after a colon (as in this case) it's a typo.

Shakakai · Accepted Answer · 2011-02-07 06:50:12Z

Yep you would be correct. That is a typo. You would call that method like so:

[obj setWidth:100.0f height:200.0f];

Referencing that method in documentation or for a method callback it should be labeled setWidth:height: (note the trailing colon). Good luck with the rest of the tutorial.

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