W7D4 - Object Oriented Design

Circle.h

//
//  Circle.h
//  Shapes
//
//  Created by Ian MacKinnon on 2015-06-18.
//  Copyright (c) 2015 Ian MacKinnon. All rights reserved.
//

#import <Foundation/Foundation.h>
#import "Shape.h"

@interface Circle : Shape

@property(nonatomic, assign)float radius;

@end

Circle.m

//
//  Circle.m
//  Shapes
//
//  Created by Ian MacKinnon on 2015-06-18.
//  Copyright (c) 2015 Ian MacKinnon. All rights reserved.
//

#import "Circle.h"

@implementation Circle


-(float) area{
   return pow(self.radius, 2) * M_PI ;
}

@end

main.m

//
//  main.m
//  Shapes
//
//  Created by Ian MacKinnon on 2015-06-18.
//  Copyright (c) 2015 Ian MacKinnon. All rights reserved.
//

#import <Foundation/Foundation.h>

#import "Rectangle.h"
#import "Circle.h"

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        // insert code here...
        
        
        Rectangle *rect1 = [[Rectangle alloc] init];
        rect1.length  = 2;
        rect1.width = 1;
        
        
        Rectangle *rect2 = [[Rectangle alloc] init];
        rect2.length  = 4;
        rect2.width = 5;
        
        Circle *circ1 = [[Circle alloc] init];
        circ1.radius = 7;
        
        
        NSArray *shapeArray = @[rect1, rect2, circ1];
        
        float sum = 0.0;
        for (Shape *shape in shapeArray){
            sum = + [shape area];
        }
        
        NSLog(@"sum of area of shapes is: %f", sum);
        
        
        
    }
    return 0;
}

Rectangle.h

//
//  Rectangle.h
//  Shapes
//
//  Created by Ian MacKinnon on 2015-06-18.
//  Copyright (c) 2015 Ian MacKinnon. All rights reserved.
//

#import <Foundation/Foundation.h>
#import "Shape.h"

@interface Rectangle : Shape

@property(nonatomic, assign) float length;
@property(nonatomic, assign) float width;

@end

Rectangle.m

//
//  Rectangle.m
//  Shapes
//
//  Created by Ian MacKinnon on 2015-06-18.
//  Copyright (c) 2015 Ian MacKinnon. All rights reserved.
//

#import "Rectangle.h"

@implementation Rectangle

-(float) area{
    return self.length * self.width;
}
@end

Shape.h

//
//  Shape.h
//  Shapes
//
//  Created by Ian MacKinnon on 2015-06-18.
//  Copyright (c) 2015 Ian MacKinnon. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface Shape : NSObject

-(float) area;

@end

Shape.m

//
//  Shape.m
//  Shapes
//
//  Created by Ian MacKinnon on 2015-06-18.
//  Copyright (c) 2015 Ian MacKinnon. All rights reserved.
//

#import "Shape.h"

@implementation Shape

-(float)area{
    [NSException raise:@"Invalid Method invocation" format:@"You called an abstract method, but Obj-C can't enforce that at compile time, so tossing this exception is our next best way of enforcing"];
    return 0.0;
}

@end

Square.h

//
//  Square.h
//  Shapes
//
//  Created by Ian MacKinnon on 2015-06-18.
//  Copyright (c) 2015 Ian MacKinnon. All rights reserved.
//

#import "Rectangle.h"

@interface Square : Rectangle

@end

Square.m

//
//  Square.m
//  Shapes
//
//  Created by Ian MacKinnon on 2015-06-18.
//  Copyright (c) 2015 Ian MacKinnon. All rights reserved.
//

#import "Square.h"

@implementation Square


-(float) area{
    return self.length *self.length;
}

@end