OC3_MyRect

//
//  MyRect.h
//  OC3_MyRect
//
//  Created by zhangxueming on 15/6/9.
//  Copyright (c) 2015年 zhangxueming. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface MyRect : NSObject
{
    int _length;
    int _width;
}

- (id)initWithLength:(int)length andWidth:(int)width;

- (int)length;

- (int)width;

- (void)setLength:(int)length andWidth:(int)width;

- (int)area;

- (void)printArea;

@end

//
//  MyRect.m
//  OC3_MyRect
//
//  Created by zhangxueming on 15/6/9.
//  Copyright (c) 2015年 zhangxueming. All rights reserved.
//

#import "MyRect.h"

@implementation MyRect

- (id)initWithLength:(int)length andWidth:(int)width
{
    self = [super init] ;
    if (self) {
        _length = length;
        _width = width;
    }
    return self;
}

- (int)length
{
    return _length;
}

- (int)width
{
    return _width;
}

- (void)setLength:(int)length andWidth:(int)width
{
    _length = length;
    _width = width;
}

- (int)area;
{
    return [self length] * [self width];
}

- (void)printArea
{
    NSLog(@"area = %i", [self area]);
}

@end

//
//  main.m
//  OC3_MyRect
//
//  Created by zhangxueming on 15/6/9.
//  Copyright (c) 2015年 zhangxueming. All rights reserved.
//

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

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        MyRect *rect = [[MyRect alloc] init];
        [rect setLength:10 andWidth:5];
        [rect printArea];
    }
    return 0;
}