Expected identifier before "{" token error

Hi I开发者_C百科 am making a demo off of "Beginning iphone Games Development" and I have the Expected identifier before "{" error on:

-(CGFloat) angle:
{
    return rotation*180.0/3.141592;
}

Can you please help?

Remove the colon after angle. The colon is telling the compiler that your method takes an argument, and it's reporting an error because there isn't one.