Question

关于objective-c中方法调用的问题

代码如下：
1-定义XYPoint接口文件#import <Foundation/Foundation.h>
@interface XYpoint : NSObject
@property int x,y;
-(void) setX:(int)xVal andY:(int) yVal;
@end

2-XYpoint实现代码
#import "XYpoint.h"
@implementation XYpoint
@synthesize x,y;
-(void) setX:(int)xVal andY:(int)yVal
{
x = xVal;
y = yVal;
}
@end

3-rectangl类接口代码
#import <Foundation/Foundation.h>
@class XYpoint;
@interface Rectangl : NSObject
@property int width,height;

-(XYpoint *) origin;
-(void) setOrigin:(XYpoint *) pt;
-(void) setWidth:(int)w andHeight:(int)y;
-(int) area;
-(int) perimeter;
@end

4-rectangl实现代码
#import "Rectangl.h"
#import "XYpoint.h"
@implementation Rectangl
{
XYpoint *origin;
}
@synthesize width,height;
-(void) setWidth:(int)w andHeight:(int)y
{
width = w;
height = y;
}
-(void) setOrigin:(XYpoint *)pt
{
origin = pt;
}
-(int) area
{
return width*height;
}
-(int) perimeter
{
return (width+height)*2;
}
-(XYpoint *) origin
{
return origin;
}
@end

5-主函数
#import <Foundation/Foundation.h>
#import "XYpoint.h"
#import "Rectangl.h"

int main(int argc, const char * argv[]) {
@autoreleasepool {
Rectangl *myrect = [[Rectangl alloc]init];
XYpoint *myPoint = [[XYpoint alloc]init];

[myPoint setX:100 andY:200];
[myrect setWidth:5 andHeight:8];

//myrect.origin = myPoint;
[myrect setOrigin:myPoint];

//NSLog(@"myrect width = %i,height = %i",myrect.width,myrect.height);
NSLog(@"myrect width = %i,height = %i",[myrect width],myrect.height);
NSLog(@"origin at (%i,%i)",myrect.origin.x,myrect.origin.y); //注释[1]
NSLog(@"area = %i,perimeter = %i",[myrect area],[myrect perimeter]);
}
return 0;
}

1、在以上代码中，rectangle的实现代码里面并没有将origin作为@property的成员，因此手写了setOrigin和origin方法，merest.origin=mypoint中，origin是-(void) origin方法还是成员变量？并且为什么在使用myrect.origin=mypoint时却自动调用了setOrigin和origin方法？
2、在rectangle实现代码中，{XYpoint *origin}是将origin当成rectangle的成员变量了吗？或者说将origin作为rectangle的属性？

Answer 1

viewController*b1=[[viewControlleralloc]init];[self.navigationControllerpushViewController:b1animated:YES];[b1release]。

追问

本人初学者，能说的明白点吗？