Review of Block

Main.m

//

Main.m

8a10. Review of Block

//

Created by Huan on 16/2/8.

copyright©2016 year Huanxi. All rights reserved.

//

#import <Foundation/Foundation.h>

function Definition

void Test () {

}

int sum (int A, int b) {

return A + b;

}

int Main (int argc, const Char * argv[]) {

@autoreleasepool {

//Insert code here ...

// review block

// What is a block on a chunk of code

What is the difference between a//block and a function

//1. functions can only be defined outside the method

//2.block can be defined within a method or can be defined outside of a method

//3.block and functions in common: all have return values and parameters

//block definition

// no return value no parameter block

void(^testblock) () = ^{

NSLog(@ " no return value no parameter block");

};

Testblock ();

// no return value for block with parameters

void(^test2block) (int) = ^ (int a) {

NSLog(@ " you are passing in %d", a);

};

Test2block (2);

// has a return value, the block with parameters

int(^sumblock) (int,int) = ^ (int A,int b) {

return A + b;

};

int result = Sumblock (2,3);

NSLog(@ " through block calculation, the result is:%d", "result");

// with return value, blcok with no parameters

//block to redefine typedef

typedef void (^mtestblock) ();

//For Blcok with no return value, no parameters - custom

mtestblock mtestblcok = ^ () {

NSLog(@ "redefined block");

};

Mtestblcok ();

// define a special operation for Blcok

typedef void (^operationblock) ();

operationblock operationblock = ^ () {

NSLog(@ " Checking for version updates ");

};

Operationblock ();

NSLog(@ "Hello, world!" );

}

return 0;

}

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Review of Block