pragma solidity 0.5.0; contract D { uint public n; address public sender; function callSetN(address _e, uint _n) public { _e.call(abi.encode(bytes4(keccak256("setN(uint256)")), _n)); } function callcodeSetN(address _e, uint _n) public view { _e.staticcall(abi.encode(bytes4(keccak256("setN(uint256)")), _n)); } function delegatecallSetN(address _e, uint _n) public { _e.delegatecall(abi.encode(bytes4(keccak256("setN(uint256)")), _n)); } }