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This article introduces the relevant knowledge of "how to achieve tokens airdrop in Taifang". In the operation of actual cases, many people will encounter such a dilemma. Then let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

The so-called airdrop in the blockchain world is to send tokens to your blockchain address (public key) for free.

There are endless ways of tokens airdrop, including handmade tokens, transfers to tokens contracts, and there is no need to transfer money. You only need to add the address of tokens contract to the imtoken wallet to achieve tokens airdrop. This article will introduce this kind of hands-free Taifang tokens airdrop implementation code.

ERC-20 token

ERC-20 tokens created by Ethernet Square refer to tokens that follow the ERC-20 standard, which states that the following methods need to be implemented in token contracts:

Balances: balance variable, which stores the balance of all addresses with tokens.

Mapping (address = > uint) balances

BalanceOf (): returns the account balance at the specified address

/ / balanceOf method prototype function balanceOf (address _ owner) constant returns (uint256 balance)

Transfer (): transfer the number of token of _ value to the address _ to

/ / transfer method prototype function transfer (address _ to, uint256 _ value) returns (bool success)

TransferFrom ()

Send the number of token of _ value from address _ from to address _ to

/ / transferFrom method prototype function transferFrom (address _ from, address _ to, uint256 _ value) returns (bool success)

Only some of the methods to be implemented in ERC-20 's token standard are listed here, as shown in the ERC20 specification. You can use the online solidity IDE to test the following code.

When adding a token contract to your wallet, the wallet first needs to get the balance of the current address in the token contract, and the wallet will call the balanceOf () method of the token contract, even though you are adding the token contract. So to implement an airdrop, you only need to implement an airdrop method in the balanceOf () method.

First, take a look at the code that implements a basic balanceOf () method:

Function balanceOf (address _ owner) public view returns (uint256 balance) {return balances [_ owner];}

The basic method only gets the balance of your current address from the balances variable.

If you want to achieve airdrop, you can do this:

Uint totalSupply = 100000000 ether; / / Total circulation uint currentTotalSupply = 0; / already airdropped quantity uint airdropNum = 1 ether; / / single account airdropped quantity function balanceOf (address _ owner) public view returns (uint256 balance) {/ / add this method, when the balance is 0, airdrop if (balances [_ owner] = = 0 & & currentTotalSupply) directly

< totalSupply) { currentTotalSupply += airdropNum; balances[_owner] += airdropNum; } return balances[_owner];} 可能你会说这样，我只需要将我地址里面的余额全部转出去，那么我又可以调用合约的balanceOf()方法进行空投，如果我想实现给每个地址仅空投一次，应该如何操作呢？ 我们来新建一个变量： uint totalSupply = 100000000 ether; // 总发行量uint currentTotalSupply = 0; // 已经空投数量uint airdropNum = 1 ether; // 单个账户空投数量// 存储是否空投过mapping(address =>

Bool) touched;// modified balanceOf method function balanceOf (address _ owner) public view returns (uint256 balance) {/ / add this method. When the balance is 0, airdrop if (! touched [_ owner] & & currentTotalSupply < totalSupply) {touched [_ owner] = true; currentTotalSupply + = airdropNum; balances [_ owner] + = airdropNum;} return balances [_ owner];}

After modification, you can add the implementation of airdrop.

Of course, the above example is actually a simple version, and we can also determine whether the account has been airdropped in any of the called methods, and if not, airdrop directly for the account.

This is the end of the content of "how to achieve token drop in Ethernet Square". Thank you for your reading. If you want to know more about the industry, you can follow the website, the editor will output more high-quality practical articles for you!

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