链式编程实现加法计算器

链式编程：是将多个操作（多行代码）通过点号(.)链接在一起成为一句代码,使代码可读性好。a(1).b(2).c(3)

特点：方法的返回值是block,block必须有返回值（本身对象），block参数（需要操作的值）

例：masonry

相关代码实现：

.h文件

@class CalculterModel;

#import <Foundation/Foundation.h>

typedef CalculterModel *(^CalculateOption) (int);

@interface CalculterModel : NSObject

@property (nonatomic, assign) int result;

@property (nonatomic, copy) CalculateOption add;

@property (nonatomic, copy) CalculateOption sub;

@property (nonatomic, copy) CalculateOption muilt;

@property (nonatomic, copy) CalculateOption divide;

@end

.m

#import "CalculterModel.h"

@implementation CalculterModel

//加

-(CalculateOption)add

{

return ^(int inputNum) {

self.result+=inputNum;

return self;

};

}

//减

-(CalculateOption)sub

{

return ^(int inputNum){

self.result-=inputNum;

return self;

};

}

//乘

-(CalculateOption)muilt

{

return ^(int inputNum){

self.result*=inputNum;

return self;

};

}

//除

-(CalculateOption)divide

{

return ^(int inputNum){

self.result/=inputNum;

return self;

};

}

实现的调用：

#import "ViewController.h"

#import "CalculterModel.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {

[super viewDidLoad];

CalculterModel *model = [CalculterModel new];

int result = model.add(123).add(222).result;

NSLog(@"result = %d",result);

}