OC5_Block

//

//  main.m

//  OC5_Block

//

//  Created by zhangxueming on 15/6/26.

//  Copyright (c) 2015年 zhangxueming. All rights reserved.

//

#import <Foundation/Foundation.h>

//block

//函数指针

int add(int a, int b)// int (*)(int , int)

{

    return a+b;

}

typedef int (* Padd)(int, int);

//block 是OC中的数据类型,用来保存一段代码块

typedef int(^ addBlock) (int, int);// int (^ ) (int , int)

typedef int (^ MyBlock) (int, int);

int main(int argc, const char * argv[]) {

    @autoreleasepool {

        Padd func=add;

        NSLog(@"add =%i", func(,));

        //不带参数的block

//        void (^printBlock)(void)= nil;

//        printBlock = ^(void)

//        {

//            NSLog(@"  *");

//            NSLog(@" ***");

//            NSLog(@"*****");

//        };

//        NSLog(@"%p", printBlock);

//        printBlock();

//        printBlock();

        //省约(void)

        void (^printBlock)(void) = ^{

            NSLog(@"  *");

            NSLog(@" ***");

            NSLog(@"*****");

        };

        printBlock();

        //带参数的block

        int (^minusBlock)(int, int)=^(int a, int b)

        {

            return a-b;

        };

        NSLog(@"sub = %i", minusBlock(,));

        //block可以直接读取block外部变量, 但是不能修改, 如果要修改block外部变量的值,需要在变量的前面 加 __block关键字

        __block int num=;

        void (^numBlock)(void)=^{

            NSLog(@"num = %i", num);

        };

        numBlock();

        void (^setNumBlock)(int) = ^(int value)

        {

            num = value;

            NSLog(@"num = %i", num);

        };

        setNumBlock();

        //block 与 typedef

        MyBlock multiBlock = ^(int a, int b)

        {

            return a*b;

        };

        NSLog(@"mul = %i", multiBlock(, ));

    }

    return ;

}