1 //
 2 //  main.m
 3   块循环最具优势！
 4  5   Created by LongMa on 2019/4/3.
 6   Copyright © 2019年. All rights reserved.
 7 //
 8 
 9 #import <Foundation/Foundation.h>
10 
11 int main(int argc,const char * argv[]) {
12     @autoreleasepool {
13         NSMutableArray *lArr1 = [NSMutableArray array];
14         NSMutableArray *lArr2 =15         for (int i = 0; i < 10; ++i) {
16             [lArr1 addObject:@(i)];
17             [lArr2 addObject:@(i)];
18         }
19         
20         反向遍历
21                 [lArr1 enumerateObjectsWithOptions:(NSEnumerationReverse)
22                                         usingBlock:^(  NSNumber* obj,NSUInteger idx,BOOL * _Nonnull stop) {
23                                             NSLog(@"%@,ind:%lu",obj,(unsigned long)idx);
24                                             if (idx == 90) {
25                                                 *stop = YES;
26                                             }
27                 }];
28         
29         
30         思考：里循环能否终止外循环?
31         A:可以实现!需要差异化小标和停止参数，然后在里层循环对外循环的stopOut进行操作！此时，对内循环stopIn是否操作会决定内循环是否能执行完毕。
32         
33         /** 2019-04-03 01:08:30.003134+0800 块循环最具优势！[3176:27943] 0,ind:0
34          2019-04-03 01:08:30.004040+0800 块循环最具优势！[3176:27943] --0,1)">35          2019-04-03 01:08:30.004143+0800 块循环最具优势！[3176:27943] --1,ind:1
36          2019-04-03 01:08:30.004679+0800 块循环最具优势！[3176:27943] --2,ind:2
37          2019-04-03 01:08:30.004756+0800 块循环最具优势！[3176:27943] --3,ind:3
38          2019-04-03 01:08:30.004819+0800 块循环最具优势！[3176:27943] --4,ind:4
39          2019-04-03 01:08:30.004881+0800 块循环最具优势！[3176:27943] --5,ind:5
40          2019-04-03 01:08:30.004914+0800 块循环最具优势！[3176:27943] --6,ind:6
41          2019-04-03 01:08:30.004945+0800 块循环最具优势！[3176:27943] --7,ind:7
42          2019-04-03 01:08:30.005036+0800 块循环最具优势！[3176:27943] --8,ind:8
43          2019-04-03 01:08:30.005072+0800 块循环最具优势！[3176:27943] --9,ind:9 */
44         [lArr1 enumerateObjectsUsingBlock:^(  NSNumber* obj,NSUInteger idxOut,BOOL * _Nonnull stopOut) {
45             NSLog(@"%@,ind:%lu",(unsigned long)idxOut);
46 
47             if (idxOut == 2) {
48                 *stopOut = YES;
49             }
50 
51             [lArr2 enumerateObjectsUsingBlock:^(id  _Nonnull obj,NSUInteger idxIn,1)"> _Nonnull stopIn) {
52                 NSLog(--%@,1)">)idxIn);
53                 if (idxIn == 354                     *stopOut =55                 }
56             }];
57 58         
59         * 2019-04-03 01:05:20.987109+0800 块循环最具优势！[3020:25596] 0,1)">60          2019-04-03 01:05:20.987380+0800 块循环最具优势！[3020:25596] --0,1)">61          2019-04-03 01:05:20.987427+0800 块循环最具优势！[3020:25596] --1,1)">62          2019-04-03 01:05:20.987476+0800 块循环最具优势！[3020:25596] --2,1)">63          2019-04-03 01:05:20.987499+0800 块循环最具优势！[3020:25596] --3,ind:3 64         [lArr1 enumerateObjectsUsingBlock:^(  NSNumber* obj,BOOL * _Nonnull stopOut) {
65             NSLog(@"%@,(unsigned long)idxOut);
66 //            
67             if (idxOut == 2) {
68                 *stopOut = YES;
69 70 71 72             [lArr2 enumerateObjectsUsingBlock:^(id  _Nonnull obj,BOOL * _Nonnull stopIn) {
73                 NSLog(@"--%@,(unsigned long)idxIn);
74                 if (idxIn == 3) {
75                     *stopIn = YES;
76                     *stopOut = YES;
77 78 79 80         }];
81         
82         
83     }
84     return 0;
85 }