黑马程序员block代码块和protocol协议

1  void (^myblock)() = ^{
2         NSLog(@"");
4     };

1  int (^sumblock)(int, int) = ^(int a, int b){
2         return a + b;
3     };
4     
5     int c = sumblock(10, 11);

 1 typedef int (^MyBlock)(int, int);
 2 myBlock sumb = ^(int a,int b){
 3         return a + b;
 4     };
 5     myBlock subb = ^(int a,int b){
 6         return a - b;
 7     };
 8     myBlock multiply = ^(int a,int b){
 9         return a * b;
10     };
11     
12     NSLog(@"\n6 + 4 = %d\n6 - 4 = %d\n6 * 4 = %d",sumb(6,4),subb(6,4),multiply(6,4));

 1 #import 
 2 
 3 @protocol TicketDelegate 
 4 
 5 // 返回票价
 6 - (double) ticketPrice;
 7 
 8 // 还剩多少张票
 9 - (int) leftTicketsNumber;
10 
11 @end

 1 #import 
 2 #import "TicketDelegate.h"
 3 
 4 @interface Person : NSObject
 5 
 6 - (void) buyTicket;
 7 
 8 // 拥有一个代理属性
 9 // id代表代理的类名随便
10 // 但必须遵守TicketDelegate协议
11 @property (nonatomic, retain) id delegate;
12 
13 @end

 1 #import "Person.h"
 2 
 3 @implementation Person
 4 
 5 // 买电影票
 6 - (void)buyTicket
 7 {
 8     // 叫代理去帮自己买票（询问一下票价、询问一下票的剩余张数）
 9     double price = [_delegate ticketPrice];
10     int number =  [_delegate leftTicketsNumber];
11     
12     NSLog(@"通过代理的帮忙，票价=%f，还剩%d张票", price, number);
13 }
14 
15 - (void)dealloc
16 {
17     [_delegate release];
18     [super dealloc];
19 }
20 @end

1 #import 
2 #import "TicketDelegate.h"
3 
4 @interface Agent : NSObject 
5 
6 @end

 1 #import "Agent.h"
 2 
 3 @implementation Agent
 4 
 5 // 剩余的票数
 6 - (int)leftTicketsNumber
 7 {
 8     // ... 亲自跑电影院\或者打电话
 9     
10     return 1;
11 }
12 
13 // 每一张票多少钱
14 - (double)ticketPrice
15 {
16     // ... 亲自跑电影院\或者打电话
17     return 1000;
18 }
19 @end

 1 #import 
 2 #import "Person.h"
 3 #import "Agent.h"
 4 int main(int argc, const char * argv[])
 5 {
 6     // 人
 7     Person *p = [[Person alloc] init];
 8     // 代理
 9     Agent *a = [[Agent alloc] init];
10     
11     // 设置人的代理
12     p.delegate = a;
13     
14     // 人打算看电影
15     [p buyTicket];
16     
17     [a release];
18     [p release];
19 }