obj-c8[block语法]

Block语法  块语法，本质上是匿名函数（没有名称的函数）C++、JS、Swift等语言，有类似语法，叫做闭包

//Block 的作用,主要是用于回调函数,解耦合

//当方法的参数是block类型,block的参数用户从内向外传值;block的返回值,用于,从外向内返回结果

#import <Foundation/Foundation.h>

#import "XunleiDownload.h"

#import "LoginManager.h"

#import "Person.h"

//int maXValue(int a, int b);
//int maXValue(int a, int b)
//{

//    return a > b ? a : b;

}

int main(int argc, const char * argv[]) {
    @autoreleasepool {
       
        //Block语法  块语法，本质上是匿名函数（没有名称的函数）C++、JS、Swift等语言，有类似语法，叫做闭包
       
//        int (*p)(int, int) = maXValue;
//        int result = p(10, 14);
//        NSLog(@"result = %d",result);
       
        //block本质是一个匿名函数,可以通过block把一个函数定义成一个变量
       
       // BOLCK和函数的相似性：（1）可以保存代码（2）有返回值（3）有形参（4）调用方式一样。
        //int (^)(int,int) block变量类型
        //myblock 变量名
        //变量的值(值是一个匿名函数)
        //int (int a, int b)
        //{
        //    return a > b ? a : b;
        //};//[有分号;]

       
       
//        int (^myBlock)(int, int) = ^int (int a, int b)
//        {
//            return a > b ? a : b;
//        };
//        int result = myBlock(15, 10);
//        NSLog(@"%d",result);
       
       
//        int (^myblock)(int) = ^int (int a)
//        {
//            int b = a * a;
//            return b;
//        };
//        int result = myblock(5);
//        NSLog(@"%d",result);
//       
        //无参无返回值
        //void (^helloBlock)(void) = ^void (void)
        //给block赋值的匿名函数,返回值类型可以直接省略不写,如果没有参数,参数列表也可以省略
//        void (^helloBlock)() = ^
//        {
//           NSLog(@"hello, world!");
//        };
//        helloBlock();
       
//        NSArray (^array)(int a) = ^(int a)
       
//        int (^stringForInt)(NSString *) = ^int (NSString * a){
//            int b = [a intValue];
//            return b;
//        };
//        int result = stringForInt(@"59");
//        NSLog(@"%d", result);
       
       
//        NSString * (^myBlock) (NSString *, NSString *) = ^NSString * (NSString * a, NSString * b){
//            NSArray * str = [a componentsSeparatedByString:b];
//            NSString * str1 = [str firstObject];
//            return str1;
//        };
//        NSString * getting = myBlock(@"www.baidu.com",@".c");
//        NSLog(@"%@",getting);
       
        //NSArray * array = [NSArray arrayWithObjects:@"henan", @"lanou", @"ios", @"17ban", nil];
       
//        NSString * (^myBlock)(NSArray *) = ^NSString * (NSArray * b){
//            NSString * str = @"";
//            for (int i = 0; i < [b count]; i++) {
//              str = [str stringByAppendingString:[b objectAtIndex:i]];
//            }
//            return str;
//        };
//        //NSArray * array = [NSArray arrayWithObjects:@"河南", @"蓝欧", @"ios", @"17班", nil];
//        NSString * string = myBlock([NSArray arrayWithObjects:@"河南", @"蓝欧", @"ios", @"17班", nil]);
//        NSLog(@"%@",string);
       
       
//         NSString * (^appendString)(NSArray *) = ^(NSArray * array){
//         NSMutableString * string = [NSMutableString stringWithCapacity:1];
//         for (NSString * str in array) {
//         [string appendString:str];
//         }
//         return string;
//         };
//        NSString * string1 = appendString([NSArray arrayWithObjects:@"河南", @"蓝欧", @"ios", @"17班", nil]);
//               NSLog(@"%@",string1);

       
       
//         NSString * (^appendString)(NSArray *) = ^(NSArray * array){
//         NSString * string = @"";
//         for (NSString * str in array) {
//         string = [string stringByAppendingString:str];
//         }
//         return string;
//         };
//       
//        NSString * string1 = appendString([NSArray arrayWithObjects:@"河南", @"蓝欧", @"ios", @"17班", nil]);
//        NSLog(@"%@",string1);
       
//        NSString * (^appendString)(NSArray *) = ^(NSArray * array){
//            NSString * string = @"";
//            for (NSString * str in array) {
//                string = [NSString stringWithFormat:@"%@%@", string, str];
//            }
//            return string;
//        };
//       
//        NSString * string1 = appendString([NSArray arrayWithObjects:@"河南", @"蓝欧", @"ios", @"17班", nil]);
//        NSLog(@"%@",string1);
       
      
       
//        XunleiDownload * dow = [[XunleiDownload alloc] init];
////        [dow download:^(int n) {
////            NSLog(@"绘制 %d 个矩形", n);
////        }];
//        [dow download:^(int n) {
//            NSLog(@"添加 %d 个圆", n);
//        }];
       
       
//        LoginManager * manager = [[LoginManager alloc] init];
//        [manager loginWithName:@"zhangsan" password:@"123456" successful:^(NSString *userName) {
//           // NSLog(@"显示用户名信息,用户名是%@",userName);
//           
//            NSLog(@"%@ 发小纸条",userName);
//        }];
       
//        LoginManager * manager = [[LoginManager alloc] init];
//        [manager loginWithName:@"zhangsan" password:@"123456" successful:^(NSString *userName) {
//            NSLog(@"%@ 发小字条",userName);
//        } failure:^(NSString *userName) {
//            NSLog(@"用户名 %@ 不存在",userName);
//        }];
       
      //  LoginManager * manager = [[LoginManager alloc] init];
//        [manager loginWithName:@"zhangsan" password:@"12345" successful:^int(NSString *userName) {
//            NSLog(@"%@ 发小字条",userName);
//        } failure:^BOOL(NSString *errorMassage) {
//            NSLog(@"%@",errorMassage);
//            return NO;
//        }];
       
//        [manager loginWithName:@"zhangsan" password:@"123456" successful:^void(NSString *userName) {
//            NSLog(@"%@ 发小字条",userName);
//        } failure:^BOOL(NSString *errorMassage) {
//            NSLog(@"%@",errorMassage);
//            return YES;
//        }];
       
       
       
//        NSArray * array = [NSArray arrayWithObjects:@"zhangsan", @"lisi", @"wanwu", @"cuiyayun", @"yingsasa", nil];
//        NSArray * newArray = [array sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
//            return [obj1 compare:obj2];
//        }];
//        NSLog(@"%@",newArray);
       
        /*
        Person * p1 = [[Person alloc] initWithName:@"zhansan" sex:@"M" age:@"19"];
        Person * p2 = [[Person alloc] initWithName:@"lisi" sex:@"M" age:@"26"];
        Person * p3 = [[Person alloc] initWithName:@"yangliu" sex:@"W" age:@"22"];
        Person * p4 = [[Person alloc] initWithName:@"heinei" sex:@"W" age:@"20"];
        Person * p5 = [[Person alloc] initWithName:@"wangwu" sex:@"M" age:@"17"];
        NSArray * array = [[NSArray alloc] initWithObjects:p1, p2, p3, p4, p5, nil];
        NSArray * newArray = [array sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
            Person * per1 = (Person *)obj1;//强转类型
            Person * per2 = (Person *)obj2;
            if (per1.age < per2.age) {
                return NSOrderedAscending;
            }else if (per2.age < per1.age){
                return NSOrderedDescending;
            }
            return NSOrderedSame;
        }];
        NSLog(@"%@",newArray);
       

        */

     

        __block int m = 3;
        //在block中使用block以外的变量,是只读的,要想该变量能在block中被修饰,使用__block进行修饰
        void (^printNumberBlock)(int a) = ^(int a){
            m = m * a;
            NSLog(@"%d",m);
        };
       
        printNumberBlock(5);
       
    }
    return 0;
}