对 'abs' 的调用不明确

Question

此错误专门发生在这一行

nRandom = abs(arc4random());

完整的方法是

void PlayLayer::update(float dt)
{
    if ( bPause || bBuy )
    {
        return;
    }
    nRandom = abs(arc4random());
    labNet->setVisible(false);
    labNetNum->setVisible(false);
    if ( mType == game_bet )
    {
        labNotice->setVisible(itemNotice->isVisible());
        labLeft->setOpacity(itemLeft->getOpacity());
        labCenter->setOpacity(itemCenter->getOpacity());
        labRight->setOpacity(itemRight->getOpacity());
        bStand = false;
        bDouble = false;
    }

    if ( mType == game_deal )
    {
        labNotice->setVisible(itemNotice->isVisible());
        labLeft->setOpacity(itemLeft->getOpacity());
        labCenter->setOpacity(itemCenter->getOpacity());
        labRight->setOpacity(itemRight->getOpacity());
        bStand = false;
    }

    if ( mType == game_play )
    {
        labNotice->setVisible(itemNotice->isVisible());
        labLeft->setOpacity(itemLeft->getOpacity());
        labCenter->setOpacity(itemCenter->getOpacity());
        labRight->setOpacity(itemRight->getOpacity());

//        if ( bStand && !bDouble)
//        {
//            this->createDealerCard();
//            this->addedDealCardEvalution();
//        }

    }

    if ( mType == game_end )
    {
        labNet->setVisible(true);
        labNetNum->setVisible(true);

        if ( mTPlay == play_lose )
        {
            labNetNum->setString(__String::createWithFormat("-$%d", nBet)->getCString());
        }
        if ( mTPlay == play_match )
        {
            labNetNum->setString("+0");
        }
        if ( mTPlay == play_win )
        {
            labNetNum->setString(__String::createWithFormat("+$%d", nBet)->getCString());
        }
        bNoticeClickEnable = false;
        labLeft->setString("");
        labLeft->setOpacity(120);
        labCenter->setString("SHUFFLE");
        labCenter->setOpacity(255);
        labRight->setString("PLAY");
        labRight->setOpacity(255);
        if ( g_nYourCoin > 200 )
        {
            nTempMaxBet = 200;
        }
        else
        {
            nTempMaxBet = g_nYourCoin;
        }
        bStand = false;



    }

    this->visibleItemCoins();
    this->drawScores();
}

Answer 1

arc4random()的签名：

uint32_t arc4random(void);

abs()的签名：

int  abs(int) __pure2;

然后当我尝试你的东西时:

abs(arc4random());

XCode 告诉我这个：

Taking the absolute value of unsigned type 'uint32_t' (aka 'unsigned int') has no effect

这引出了一个问题，为什么你需要 un 有符号整数的绝对值？

假设您没有使用负数，那么您可以将随机值直接分配给您的变量。如果可能的话，我会建议将它转换为 uint32_t 以外的东西。在不知道 nRandom 是什么的情况下，我无法告诉您将其转换为什么。

对 'abs' 的调用不明确

Call to 'abs' is ambiguous

xcode

objective-c++

cocos2d-iphone

ios