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iOS Objective-C Basics (Retired) Introduction to Objective-C From Structs to Objects

John Saunders
John Saunders
288 Points

Repeating declarations more than once in code.

In the code below, why is _radius = radius; initialized twice? Once at the top and once at the bottom.

import "Sphere.h"

@implementation Sphere

-(void)setRadius:(float)radius { _radius = radius; }

-(float)radius { return _radius; }

-(void)setCenter:(NSArray *)center {

_center = center;


-(NSArray *)center { return _center; }

-(void)setCenter:(NSArray *)center radius:(float)radius { _center = center; _radius = radius;

} @end

1 Answer

That last method looks like a convenience method for setting the center and radius in one go, rather than calling setRadius: and setCenter: separately. The code looks valid as-is but it would be better practice to do something like this:

- (void)setCenter:(NSArray *)center radius:(float)radius {
    [self setCenter:center];
    [self setRadius:radius];