oc 旧版语法糖

//
//  ViewController.m
//  OC 演练代码
//
//  Created by lzy on 2018/11/12.
//  Copyright © 2018 lzy. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    UILabel *l=[UILabel alloc]initWithFrame:CGRectMake(0, 20, 100, 40);
    l.text=@"word";
    [self.view addSubview:l];
    
    // 拓展知识点
    UILabel *myLabel=({
        UILabel *l=[UILabel alloc]initWithFrame:CGRectMake(0, 280, 100, 40);
        l.text=@"word";
        [self.view addSubview:l];
        // l末尾给mylabel 设置数值；
        
        l;
    });
    
    NSLog(@"---%@",myLabel);
    
    
    
    // 花括号可以包装一段代码
    
    {
        UILabel *l=[UILabel alloc]initWithFrame:CGRectMake(0, 20, 100, 40);
        l.text=@"word";
        [self.view addSubview:l];
    }
    
}


-(void)demoSwith{
    int num=10;
    
    switch (num) {
        case 10:{
            NSString *name=@"张";
            NSLog(@"%@优秀",name);
            
            // 花括号限定变量的作用域名
        }
            
            
            break;
            
        default:
              NSLog(@"一般");
            break;
    }
}

@end