Who is who in solidity?

Question

pragma solidity ^0.8.4;

contract Contract {
    address payable public owner;
    address payable public charity;

    constructor(address payable _charity) {
        owner = payable(msg.sender);
        charity = _charity;
    }

    receive() external payable { }

    function donate() public {
        charity.transfer(address(this).balance);
    }

    function tip() public payable {
        owner.transfer(msg.value);
    }
}

msg.sender is the person deploys the contract

charity is charity

address(this) is contract address

When I use donate function "msg.value" sent to charity from owner ? But I use address(this).balance in this function. I dont use owner.

I dont understand what is happened when I use tip function ?

Answer 1

The donate() function sends all the ETH of the contract to the address specified in the charity var.

The tip() function requires you to send ETH with your transaction. This is then transferred to the address specified in the owner var.

So if you are calling tip() from the owner address you are creating a tx which sends ETH to yourself.