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@nhancv
Last active August 2, 2023 08:13
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WETH
// SPDX-License-Identifier: GNU GENERAL PUBLIC LICENSE V3
pragma solidity 0.5.16;
contract WETH {
string public name = "Wrapped Ether";
string public symbol = "WETH";
uint8 public decimals = 18;
event Approval(address indexed src, address indexed guy, uint256 wad);
event Transfer(address indexed src, address indexed dst, uint256 wad);
event Deposit(address indexed dst, uint256 wad);
event Withdrawal(address indexed src, uint256 wad);
mapping(address => uint256) public balanceOf;
mapping(address => mapping(address => uint256)) public allowance;
function() external payable {
deposit();
}
function deposit() public payable {
balanceOf[msg.sender] += msg.value;
emit Deposit(msg.sender, msg.value);
}
function withdraw(uint256 wad) public {
require(balanceOf[msg.sender] >= wad);
balanceOf[msg.sender] -= wad;
msg.sender.transfer(wad);
emit Withdrawal(msg.sender, wad);
}
function totalSupply() public view returns (uint256) {
return address(this).balance;
}
function approve(address guy, uint256 wad) public returns (bool) {
allowance[msg.sender][guy] = wad;
emit Approval(msg.sender, guy, wad);
return true;
}
function transfer(address dst, uint256 wad) public returns (bool) {
return transferFrom(msg.sender, dst, wad);
}
function transferFrom(
address src,
address dst,
uint256 wad
) public returns (bool) {
require(balanceOf[src] >= wad);
if (src != msg.sender && allowance[src][msg.sender] != uint256(-1)) {
require(allowance[src][msg.sender] >= wad);
allowance[src][msg.sender] -= wad;
}
balanceOf[src] -= wad;
balanceOf[dst] += wad;
emit Transfer(src, dst, wad);
return true;
}
}
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