I'm going through some training on objective-c. The trainer suggests setting single character parameter names. The .NET developer in me is crying. Is this truly the convention? Why?

For example,

@interface Square : NSObject
{
  int size;
}

-(void)setSize: (int)s;

I've seen developers using underscores int _size to declar variables (I think people call the variable declared in @interface ivar for some unknown reason). Personally, I prefer to use descriptive names. E.G.

@interface Square : NSObject
{
  int Size;
}

-(void)setSize: (int)size;

C, like C# is case sensitive. So why don't we use the same convention as .NET?