Fallback Function.srt

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let's talk about the fallback function
让我们来谈谈合约中的后备功能，您可以定义一个

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inside the contract you can define a
让我们来谈谈合约中的后备功能，您可以定义一个

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special function called the fallback
称为后备功能的特殊功能，您可以像这样操作

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function and you can do it like this the
称为后备功能的特殊功能，您可以像这样操作

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function cannot have a name it cannot
函数不能具有名称，不能接受任何输入，也不能返回任何名称

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take any inputs and it cannot return any
函数不能具有名称，不能接受任何输入，也不能返回任何名称

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output and they must be declared as
输出，并且必须将它们声明为外部，现在此函数将是

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external now this function will be
输出，并且必须将它们声明为外部，现在此函数将是

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called in two situations one when you
在两种情况下调用：一种是在您调用不存在的函数时-当

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call function that does not exist - when
在两种情况下调用：一种是在您调用不存在的函数时-当

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you send either to this contract by sand
您可以通过沙沙转移或致电发送给该合同，并为此

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transfer or call and in order for this
您可以通过沙沙转移或致电发送给该合同，并为此

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contract to receive either the fallback
接受后备功能的合同必须声明为应付账款，并且

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function must be declared as payable and
接受后备功能的合同必须声明为应付账款，并且

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inside the function you can write your
在函数内部，您可以像常规函数一样在此处编写代码，但是它

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code here like a regular function but it
在函数内部，您可以像常规函数一样在此处编写代码，但是它

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is recommended not to write almost any
建议不要在其中写任何代码，原因是

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code inside here the reason is that when
建议不要在其中写任何代码，原因是

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you send either by hand or transfer it
您可以手动发送或转移2300次喘息-这种后备

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for its 2300 gasps - this fallback
您可以手动发送或转移2300次喘息-这种后备

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function which is enough gas to email or
该功能足以发送电子邮件或日志，但没有足够的电量来写入

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log but not enough gas to write to
该功能足以发送电子邮件或日志，但没有足够的电量来写入

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storage or call another contract and to
存储或调用其他合同，并向您显示转发和转移

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show you that send and transfer forwards
存储或调用其他合同，并向您显示转发和转移

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2300 gas we're gonna use a special
2300汽油我们将在这里使用一种特殊的功能，称为汽油剩余

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function here called gas left that
2300汽油我们将在这里使用一种特殊的功能，称为汽油剩余

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returns the remaining gas and we'll
返回剩余的气体，我们将更新dog事件以返回

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update our dog event to return the
返回剩余的气体，我们将更新dog事件以返回

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amount of gas left we'll also create a
剩余的气体量，我们还将创建一个辅助函数，以返回余额

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helper function that returns the balance
剩余的气体量，我们还将创建一个辅助函数，以返回余额

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of ether stored in this contract next
储存在该合约中的以太币接下来，我们将创建一个合约

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we're going to create a contract that
储存在该合约中的以太币接下来，我们将创建一个合约

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will send either to the contract above
将发送给以上合同，这将触发后备功能

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which will trigger the fallback function
将发送给以上合同，这将触发后备功能

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the first function that we're going to
我们将要创建的第一个函数称为转移下降

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create will be called transfer to fall
我们将要创建的第一个函数称为转移下降

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back after we deployed these two
在我们将这两个合同部署到这里之后，我们将通过

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contracts here we're going to pass in
在我们将这两个合同部署到这里之后，我们将通过

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the address of the fallback contract
以上备用合同的地址，我们将使用

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above and we're gonna send either using
以上备用合同的地址，我们将使用

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the transfer method transfer forwards
转移方法转移2300瓦斯，之后当我们实际呼叫时

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2300 gas and later when we actually call
转移方法转移2300瓦斯，之后当我们实际呼叫时

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this function here you'll be able to see
使用此功能，您现在可以看到剩余气体少于2300

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that the gas left is less than 2300 now
使用此功能，您现在可以看到剩余气体少于2300

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recall that sending neeterb like all
回想一下，像福特一样向所有公司派遣neeterb的所有气体

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Ford's all the gas to the fallback
回想一下，像福特一样向所有公司派遣neeterb的所有气体

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function and in that case gas theft can
功能，在这种情况下，煤气盗窃可能会超过2300，并向您显示

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be greater than 2300 and to show you a
功能，在这种情况下，煤气盗窃可能会超过2300，并向您显示

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demo of this we're going to create a
此演示我们将创建一个函数，该函数将调用

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function that's going to call the
此演示我们将创建一个函数，该函数将调用

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fallback contract above using the call
使用调用的后备合同，我们将此函数命名为

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and we'll name this function call
使用调用的后备合同，我们将此函数命名为

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fallback
后备广告，我们将使用call方法发送

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we'll send either using the call method
后备广告，我们将使用call方法发送

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and make sure that it was able to send
并确保它能够发送食者

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the eater
并确保它能够发送食者

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now let's deploy the contract execute
现在让我们部署合同来执行功能，我将逐步指导您

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the functions and I'll walk you through
现在让我们部署合同来执行功能，我将逐步指导您

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how the codes are executed
代码如何执行

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so here I've deployed the two contracts
所以在这里，我部署了两个合同，即后备合同

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the fallback contract that's going to be
所以在这里，我部署了两个合同，即后备合同

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receiving the ETA and sent to for that
接收预计到达时间并发送给该合同的合同，该合同将发送

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contract that's going to be sending the
接收预计到达时间并发送给该合同的合同，该合同将发送

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heater and let's go over the transfer to
加热器，让我们先谈谈向后备功能的转移，我要

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fallback function first so I'm gonna
加热器，让我们先谈谈向后备功能的转移，我要

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copy and paste the address of the
在此处复制并粘贴后备合同的地址，然后发送一个

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fallback contract here and send one
在此处复制并粘贴后备合同的地址，然后发送一个

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either when we check the transaction log
或者当我们检查交易记录时，您可以在此处看到记录为2255

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you can see here that it logged 2255
或者当我们检查交易记录时，您可以在此处看到记录为2255

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gasp so when we call the transfer to
喘着粗气，所以当我们调用转移到后备功能时，它将以太发送到

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fallback function it sent the ether to
喘着粗气，所以当我们调用转移到后备功能时，它将以太发送到

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the fallback contract above using the
上面的后备合同使用转移方法触发了

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transfer method which triggered the
上面的后备合同使用转移方法触发了

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fallback function inside the fallback
后备合同内的后备功能，以及自转移以来

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contract and since transfer forwards
后备合同内的后备功能，以及自转移以来

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2300 gas by the time the cold reached
到这里的冷气到达2300瓦斯时，它已经使用了一些瓦斯和瓦斯

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here it used some of the gas and gas
到这里的冷气到达2300瓦斯时，它已经使用了一些瓦斯和瓦斯

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theft returned an amount less than 2300
盗窃返回的金额小于2300，在这种情况下，下一个我返回2255

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in this case it returned 2255 next I
盗窃返回的金额小于2300，在这种情况下，下一个我返回2255

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want to show you that the call method is
想要告诉您调用方法将转发所有气体，所以再次

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going to forward all of the gas so again
想要告诉您调用方法将转发所有气体，所以再次

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I'm gonna copy the address of the
我要在此处复制后备合同的地址，然后发送一个

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fallback contract here and then send one
我要在此处复制后备合同的地址，然后发送一个

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ether again
再次以太

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and let's check the transaction log then
让我们检查事务日志，然后您可以在此处看到它转发了更多内容

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you can see here that it forwarded more
让我们检查事务日志，然后您可以在此处看到它转发了更多内容

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than two thousand three hundred gasps
超过23300次喘息，与之前的示例类似

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similar to the previous example when we
超过23300次喘息，与之前的示例类似

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called the function called fallback this
称为回退功能，此功能将以太币发送至回退合约

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sent the ethers to the fallback contract
称为回退功能，此功能将以太币发送至回退合约

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by the call method which forwarded all
通过转发所有喘气的调用方法，回退功能是

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of the gasps the fallback function was
通过转发所有喘气的调用方法，回退功能是

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executed and involved the remaining gas
执行并涉及剩余的天然气，这是这里的数量，因此总之

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which is this amount here so in summary
执行并涉及剩余的天然气，这是这里的数量，因此总之

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the fallback function receives two
备用功能在收到后会收到两千三百次喘息

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thousand three hundred gasps when it is
备用功能在收到后会收到两千三百次喘息

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invoked by the send or transfer method
由send或transfer方法调用，但在发送时可以接收更多气体

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but it can receive more gas when it is
由send或transfer方法调用，但在发送时可以接收更多气体

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invoked by the call method the call
通过call方法调用，call方法可以将所有气体提供给

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method can afford all of the gas to the
通过call方法调用，call方法可以将所有气体提供给

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fallback function which means that you
后备功能，这意味着您可以像编写常规功能一样编写代码

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can write code like a regular function
后备功能，这意味着您可以像编写常规功能一样编写代码

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to execute inside the fallback function
在后备功能内执行，但建议不要写太多

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but it is recommended not to write much
在后备功能内执行，但建议不要写太多

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cold inside it since the function can
内部温度过低，因为如果使用过多的气体，该功能可能会失败，这意味着

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fail if it uses too much gas which means
内部温度过低，因为如果使用过多的气体，该功能可能会失败，这意味着

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that you won't be able to send either to
您将无法使用“发送”或“转移”将其发送到合同

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the contract using the send or transfer
您将无法使用“发送”或“转移”将其发送到合同

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method so that's all I got for this
方法，如果您有任何问题，请放心，这就是我为这部影片所拍摄的全部内容

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video if you have any questions let me
方法，如果您有任何问题，请放心，这就是我为这部影片所拍摄的全部内容

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know in the comments below have a nice
知道在下面的评论中度过了愉快的一天，我很快会在下一个与您见面

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day and I'll see you soon in the next
知道在下面的评论中度过了愉快的一天，我很快会在下一个与您见面

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video
视频