how do I set the values of an array in Objective-C using .notation? - objective-c

Question

Sorry I'm new to Objective-C and I'm still figuring out how to set properties using dot notation. I have 3 files as follows... towards the end(in main), I've set the radius property and the logged it, but I'm not sure how to set the center property because it's not a float (like radius) it's an array. I originally tried something like—
ball.center = {12, 14, 16} does not work.
My class .m file is:
#implementation Sphere
-(void)setCenter:(NSArray *)center radius:(float)radius {
_center = center;
_radius = radius;
}
#end
my class .h file is:
#interface Sphere : NSObject
#property (nonatomic) float radius;
#property (nonatomic, strong) NSArray *center;
-(void)setCenter:(NSArray *)center radius:(float)radius;
#end
and my main file is:
int main(int argc, const char * argv[])
{
#autoreleasepool {
Sphere *ball = [[Sphere alloc] init];
ball.radius = 34;
**// ball.center = an array, so how do we set that?**//
**//do I have to set the values of the array first?//**
NSLog(#"\nball radius %f\n", ball.radius);
**//I want to be able to log the values of the array the way I logged the radius.**
}
return 0;
}

Answer 1

I'll reply to your question "how I can create an array with numbers", but it looks like you don't need an array at all (read all the answer :-))
The first thing that you need is to initialize your array, for example:
NSArray *array = [NSArray arrayWithObjects:object1, object2, object3, nil];
There is also the literal that allows you to do the same thing with a friendly synthax
NSArray *array = #[object1, object2, object3];
Note that you can only insert objects in an NSArray and not primitives, so you need some NSNumber (a NSNumber is an object that represents a number).
You can use a class method to create a NSNumber
NSNumber *one = [NSNumber numberWithInt:1];
Or the literal synthax (usually preferred for its brevity)
NSNumber *one = #(1);
So, something like this will do
NSArray *array = #[#(1), #(2), #(3)];
However, I see that you want to represent the center, usually to do it, you don't use an array of objects, you use a CGPoint, that is not an array, it is a struct that contains 1 point (i.e. X and Y), and it is perfect to represent the center!
So the code will look like:
#implementation Sphere
-(void)setCenter:(CGPoint)center radius:(float)radius {
_center = center;
_radius = radius;
}
#end
and to use it:
Sphere *ball = [[Sphere alloc] init];
ball.center = CGPointMake(10, 20);
NSLog(#"my ball center x:%d y:%d", ball.center.x, ball.center.y);