IWETH.sol

pragma solidity ^0.5.16;

interface IWETH {
    // ERC20 Optional Views
    function name() external view returns (string memory);

    function symbol() external view returns (string memory);

    function decimals() external view returns (uint8);

    // Views
    function totalSupply() external view returns (uint);

    function balanceOf(address owner) external view returns (uint);

    function allowance(address owner, address spender) external view returns (uint);

    // Mutative functions
    function transfer(address to, uint value) external returns (bool);

    function approve(address spender, uint value) external returns (bool);

    function transferFrom(
        address from,
        address to,
        uint value
    ) external returns (bool);

    // WETH-specific functions.
    function deposit() external payable;

    function withdraw(uint amount) external;

    // Events
    event Transfer(address indexed from, address indexed to, uint value);
    event Approval(address indexed owner, address indexed spender, uint value);
    event Deposit(address indexed to, uint amount);
    event Withdrawal(address indexed to, uint amount);
}