求助为什么这里的lambda不能用引用捕获？会报错!

2018-04-25 11:36:42 853 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

C++11 lambda表达式不能捕获map/unordered_map值先看一道面试题。某公司中有N名员工，给定所有员工工资的清单,财务人员要按照持定的顺序排列员工的工资,他按照工资的频次降序排列,即给定清单中所有频次较高的工资将在频次较低的工资之前出现，如果相同数量的员工都有相同的工资，则将按照给定清单中该工资第一次出现的顺序排列。写一算法来帮助财务人员排列员工工资的顺序。输入：该函数/方法的输入包括两个参数—— num,一个整数，表示员工的人数。 s... 阅读详情

图3中值传递没问题，引用就会报错，歪？

#include "HelloWorldScene.h"

#include "SimpleAudioEngine.h"

#include "ui/CocosGUI.h"

USING_NS_CC;



Scene* HelloWorld::createScene()

{

    return HelloWorld::create();

}



// Print useful error message instead of segfaulting when files are not there.

static void problemLoading(const char* filename)

{

    printf("Error while loading: %s\n", filename);

    printf("Depending on how you compiled you might have to add 'Resources/' in front of filenames in HelloWorldScene.cpp\n");

}



// on "init" you need to initialize your instance

bool HelloWorld::init()

{

    //////////////////////////////

    // 1. super init first

    if ( !Scene::init() )

    {

        return false;

    }



    auto visibleSize = Director::getInstance()->getVisibleSize();

    Vec2 origin = Director::getInstance()->getVisibleOrigin();

	// add "HelloWorld" splash screen"

	sprite = Sprite::create("HelloWorld.png");

	if (sprite == nullptr)

	{

		problemLoading("'HelloWorld.png'");

	}

	else

	{

		// position the sprite on the center of the screen

		sprite->setPosition(Vec2(visibleSize.width / 2 + origin.x, visibleSize.height / 2 + origin.y));

		// add the sprite as a child to this layer

		this->addChild(sprite, 0);

	}

    /////////////////////////////

    // 2. add a menu item with "X" image, which is clicked to quit the program

    //    you may modify it.



    // add a "close" icon to exit the progress. it's an autorelease object

    auto closeItem = MenuItemImage::create(

                                           "CloseNormal.png",

                                           "CloseSelected.png",

										   CC_CALLBACK_1(HelloWorld::menuCloseCallback, this, sprite));



    if (closeItem == nullptr ||

        closeItem->getContentSize().width <= 0 ||

        closeItem->getContentSize().height <= 0)

    {

        problemLoading("'CloseNormal.png' and 'CloseSelected.png'");

    }

    else

    {

        float x = origin.x + visibleSize.width - closeItem->getContentSize().width/2;

        float y = origin.y + closeItem->getContentSize().height/2;

        closeItem->setPosition(Vec2(x,y));

    }



    // create menu, it's an autorelease object

    auto menu = Menu::create(closeItem, NULL);

    menu->setPosition(Vec2::ZERO);

    this->addChild(menu, 1);



    /////////////////////////////

    // 3. add your codes below...



    // add a label shows "Hello World"

    // create and initialize a label



    auto label = Label::createWithTTF("Hello World", "fonts/Marker Felt.ttf", 24);

    if (label == nullptr)

    {

        problemLoading("'fonts/Marker Felt.ttf'");

    }

    else

    {

        // position the label on the center of the screen

        label->setPosition(Vec2(origin.x + visibleSize.width/2,

                                origin.y + visibleSize.height - label->getContentSize().height));

        this->addChild(label, 1);

    }

	auto pBut1 = ui::Button::create("CloseNormal.png","CloseSelected.png");

	pBut1->setAnchorPoint(Vec2::ZERO);

	pBut1->addTouchEventListener(CC_CALLBACK_2(HelloWorld::ContralMoveTest, this, sprite));

	this->addChild(pBut1);



    return true;

}

void HelloWorld::ContralMoveTest(Ref *sender,ui::Widget::TouchEventType controlEvent, Sprite* pSprite){

	if (!isScheduled("HelloWorld::ContralMoveTest")){

		this->schedule([=](float dt){

			pSprite->setPositionX(pSprite->getPositionX() + 1.0f);

		}, 0, -1, 0, "HelloWorld::ContralMoveTest");

	}

	//离开状态结束定时器

	if (controlEvent == ui::Widget::TouchEventType::ENDED) {

		this->unschedule("HelloWorld::ContralMoveTest");

	}

}



void HelloWorld::menuCloseCallback(Ref* pSender, Sprite* pSprite)

{



}



void HelloWorld::SchedulerTest(float dt, Sprite* pSprite)

{

	pSprite->setVisible(!pSprite->isVisible());

}