块操作 Block

//
//  main.m
//  块操作 Block
//
//  Created by MAC on 15/12/24.
//  Copyright © 2015年 MAC. All rights reserved.
//

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
       /*
        1.Block [] 匿名函数 闭包 c叫函数指针
        2.Block语法格式
        return type (^BlockName)(list of arguments)=^(list of arguments){body}
        */
        
        void(^TestBlock)(void)=^(void){
            NSLog(@"Hello Block");
        };
        TestBlock();
        int(^SumBlock)(int a,int b)=^(int a,int b){
            return a+b;
        };
        NSLog(@"sum =%d",SumBlock(1,2));
        //访问外部变量 要加__block
        __block int x =100;
        void(^ChangeBolck)(void)=^(void){x=200;};
        ChangeBolck();
        NSLog(@"x=%d",x);
        
        //3.如何直接使用Block
        NSArray *array = @[@"4",@"2",@"5",@"9"];
        //进行排序
        array = [array sortedArrayUsingComparator:^NSComparisonResult(id  _Nonnull obj1, id  _Nonnull obj2) {
            return [obj1 compare:obj2];
        }];
        NSLog(@"%@",array);
        
        
        //4.类型定义typedif
        typedef void (^MyBlock)(void);
        MyBlock b = ^(void){NSLog(@"Hello World");};
        b();
        typedef int (^Sumblock)(int a,int b);
        Sumblock s = ^(int a,int b){return a+b;};
        s(1,5);
        //5.本地变量在代码块的作用域（常量）
       __block int a = 100,c= 200; //常量使用 const
        int(^Sunblock1)(void)=^(void){return a+c;};//使用第一次的值 100 200 后面值的改变不会影响
        NSLog(@"%d",Sunblock1());
        a = 22;
        c = 22;
        NSLog(@"%d",Sunblock1());//结果都是300
        //6.全局变量
       static int aa = 100,cc= 200; //设定为static 都可以访问
        int(^Sunblock2)(void)=^(void){return aa+cc;};
        NSLog(@"%d",Sunblock2());
        aa = 22;
        cc = 22;
        int xx = Sunblock2();
        NSLog(@"%d",xx);//结果44
        
    }
    return 0;
}