XCode 开发时,一个小BUG,记录之.

1):Rectangle.h

//

//  Created by dhanzhang on 10-6-11.

//  Copyright 2010 __MyCompanyName__. All rights reserved.

//

 

#import <Cocoa/Cocoa.h>

 

 

@interface Rectangle : NSObject {

int width;

int height;

}

 

-(Rectangle*) initWithWidth: (int) w height: (int) h;

-(void) setWidth: (int) w;

-(void) setHeight: (int) h;

-(void) setWidth: (int) w height: (int) h;

-(int) width;

-(int) height;

-(void) print;

 

@end

 

 

@interface Square: Rectangle

-(Square*) initWithSize: (int) s;

-(void) setSize: (int) s;

-(int) size;

@end

 

@implementation Rectangle

-(Rectangle*) initWithWidth: (int) w height: (int) h {

    self = [super init];

    if ( self ) {

        [self setWidth: w height: h];

    }

    return self;

}

 

-(void) setWidth: (int) w {

    width = w;

}

 

-(void) setHeight: (int) h {

    height = h;

}

 

-(void) setWidth: (int) w height: (int) h {

    width = w;

    height = h;

}

 

-(int) width {

    return width;

}

 

-(int) height {

    return  height;

}

 

-(void) print {

    printf( "width = %i, height = %i", width, height );

}

@end

 

//-----------Square

@implementation Square

-(Square*) initWithSize: (int) s {

    self = [super init];

    if ( self ) {

        [self setSize: s];

    }

    return self;

}

 

-(void) setSize: (int) s {

    width = s;

    height = s;

}

 

-(int) size {

    return width;

}

 

-(void) setWidth: (int) w {

    [self setSize: w];

}

 

-(void) setHeight: (int) h {

    [self setSize: h];

}

@end

 

------------------调用时的一个小问题---------

void RECT()

{

Rectangle *rec = [[Rectangle alloc] initWithWidth: 10 height: 20];

 

    Square *sq = [[Square alloc]  initWithSize:13 ];//------------Build  失败.....

    //正确的写法如下:

   /*-------不知道会不会造成泄露

    Square *sq = [[Square alloc]  init ];

    [sq initWithSize:13];//----调用了2次?

   */ 

  //或者如下   

    Square *sq = [(Square *)[Square alloc]  initWithSize:13 ];

 

    [sq setWidth: 20];  

    [sq print]; 

    [rec release];

    [sq release];

}