LHF Objective-C语法（6）继承

MyRectangle.h

//==========================================
#import <Foundation/Foundation.h>

@interface MyRectangel:NSObject{
	int width;
	int height;
}

-(MyRectangel*) initWithWidth:(int) weight andHeight:(int) height;
-(void) setWidth:(int) width;
-(void) setHeight:(int) height;

-(int)width;
-(int)height;
-(void) area;
@end

//===============================================
#import "MyRectangle.h"

-(MyRectangel*) initWithWidth:(int) weight andHeight:(int) height{
	self = [supert init];
	if(self){
		[self setWidth:w];
		[self setHeight:h];
	}
}

-(void) setWidth:(int) w{
	width = w;
}

-(void) setHeight:(int) h{
	height = h;
}

-(int)width{
	return width;
}

-(int)height{
	return height;
}

-(void) area{
	NSLog(@"%d",width*height);
}
@end

正方形

//正方形继承矩形===============================================
#import "MyRectangle.h"

@interface MySquare:MyRectangle{
	int size;
}

-(MySquare*) initWithSize:(int)size;
-(void) setSize:(int) size;

-(int)size;
@end
//===============================================
#import "MySquare.h"

@implementation MySquare
-(MySquare*) initWithSize:(int)s{
	self = [super init];
	if(self){
		[self setWidth:s];
		[self setHeight:s];
	}
	//return self;	
}

-(void) setSize:(int) s{
	size = s;
}

-(int)size{
	return size;
}
@end

main.m

//===============================================
@import "MySquare.h"
int main(argc,const char * argv[]){

	MyRectangel *r = [[MyRectangle alloc] initWithWidth:2 andHeight:5];
	[r area];

	MySquare *s = [[MySquare alloc] initWithSize:6];
	[s area];//调用父类的方法，计算面积

	[r release];
	[s release];
}