etherLock.sol

//SPDX-License-Identifier: AFL-3.0 (Academic Free License v3.0) https://opensource.org/licenses/afl-3.0
//code by Harsh Strongman from lifemathmoney.com, the #1 self-improvement website for men

//solidity version specifier
pragma solidity 0.8.1;

//This contract locks in Ether for 1 year to help the owner with a savings habit

contract etherLock {

    address payable owner;
    uint startTime;

    //Set the start time to when the contract is created and save the creator's address
    constructor() {
        owner = payable(msg.sender);
        startTime = block.timestamp;
    }

    //function to recieve ether
    receive() external payable {}

    function withdraw() public {
        //check if 1 year has passed (1 year has 31536000 seconds)
        require((block.timestamp - startTime) > 31536000, "1 year has not yet passed");
        //send ether
        owner.transfer(address(this).balance);
    }
}