funWithDelegatesAndCalls.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;


contract A {
    uint public num;
    address public sender;
    uint public value;
    
    function setVars(uint _num) public payable {
        num = _num;
        sender = msg.sender;
        value = msg.value;
    }

    function setVarsDelegated(address _contract, uint _num) public payable {
        // A's storage is set, B is not modified.
        (bool success, bytes memory data) = _contract.delegatecall(
            abi.encodeWithSignature("setVars(uint256)", _num)
        );
    }
    
    function setVarsCalled(address _contract, uint _num) public payable {
        // A's storage is set, B is not modified.
        (bool success, bytes memory data) = _contract.call(
            abi.encodeWithSignature("setVars(uint256)", _num)
        );
    }
}