Withdraw Ether From Smart Contract

So far we have sent Ether to our Smart Contract. But there is currently no way to get Ether back out again! So, what’s next? Yes! A function to withdraw Ether would be good, ey?!

Add a Withdraw Function

Let’s add the following function to the Smart Contract:

 
// SPDX-License-Identifier: GPL-3.0
 
pragma solidity ^0.8.1;
 
contract SendMoneyExample {
    
    uint public balanceReceived;
    
    function receiveMoney() public payable {
        balanceReceived += msg.value;
    }
    
    function getBalance() public view returns(uint) {
        return address(this).balance;
    }
 
    function withdrawMoney() public {
        address payable to = payable(msg.sender);
        to.transfer(getBalance());
    }
}

This function will send all funds stored in the Smart Contract to the person who calls the “withdrawMoney()” function.

Deploy the new Smart Contract

Let’s try this:

1. Deploy the new version and send again 1 Ether to the Smart Contract.
2. To avoid confusion I recommend you close the previous Instance, we won’t need it anymore

At the end you should end up with one active Instance of your Smart Contract.

The same procedure as before:

1. Put in “1 Ether” into the value input box
2. hit “receiveMoney” in your new contract Instance

Your balance should be 1 Ether again:

Withdraw Funds from the Smart Contract

Now it’s time we use our new function! But to make things more exciting, we’re going to withdraw to a different Account.

Select the second Account from the Accounts dropdown:

Then hit the “withdrawMoney” button:

Observe the amount of Ether you have now in your Account:

It’s more than the previous 100 Ether! We got our 1 Ether through our Smart Contract into another Account! AWESOME!

While we can withdraw our funds now, the whole function itself is pretty useless, isn’t it?! Anyone can withdraw funds to his Account. There are no fractions of the Amount - all in all, pretty insecure.

I still hope the concept is a bit clearer now!

Let’s to another function, which allows us the send the full amount to a specific Address! It will still be insecure, but at least teaches a new concept - one at a time!

Alright, let’s do this on the next page!