Objective-C Dynamic Binding

/* Objective-C Dynamic Binding - Example Program */
		
#import <Foundation/Foundation.h>
@interface SQUARE:NSObject
{
	float area;
}
- (void)calculate_area_of_side:(CGFloat)side;
- (void)print_area;
@end

@implementation SQUARE
- (void)calculate_area_of_side:(CGFloat)side
{
	area = side * side;
}
- (void)print_area
{
	NSLog(@"The area of square = %f", area);
}
@end

@interface RECTANGLE:NSObject
{
	float area;
}
- (void)calculate_area_of_length:(CGFloat)length andBreadth:(CGFloat)breadth;
- (void)print_area;
@end

@implementation  RECTANGLE
- (void)calculate_area_of_length:(CGFloat)length andBreadth:(CGFloat)breadth
{
	area = length * breadth;
}
- (void)print_area
{
	NSLog(@"The area of Rectangle = %f", area);
}
@end

int main()
{
	SQUARE *square = [[SQUARE alloc]init];
	[square calculate_area_of_side:10.0];
	RECTANGLE *rectangle = [[RECTANGLE alloc]init];
	[rectangle calculate_area_of_length:10.0 andBreadth:5.0];
	NSArray *shapes = [[NSArray alloc]initWithObjects: square, rectangle,nil];
	id object1 = [shapes objectAtIndex:0];
	[object1 print_area];
	id object2 = [shapes objectAtIndex:1];
	[object2 print_area];
	
	return 0;
}