Blockchain By Example

The constructor

Every contract must contain a constructor function that is run only once when the contract is first deployed. In our implementation, the constructor takes the initial supply of tokens as a parameter, which is assigned to the owner of the contract. We also emit a Transfer event, indicating a transfer from address 0 to the contract owner's account. This is considered best practice, but is not required by the standard:

constructor(uint256 _initialSupply) public {    balanceOf[msg.sender] = _initialSupply;    totalSupply = _initialSupply;    emit Transfer(address(0), msg.sender, totalSupply);}

We've now written sufficient code to have a functional token, though there are still things we must add before it adheres completely to the ERC-20 ...