add live exo

6. Dapp/3_1_web3/.gitignore

@@ -1,2 +1,3 @@
 .env
+dotenv/
 node_modules/

6. Dapp/3_2_lectureSC/.gitignore

@@ -1,2 +1,3 @@
 .env
+dotenv/
 node_modules/

6. Dapp/Live_Hhat_SSdap/backend/.gitignore

@@ -0,0 +1,11 @@
+node_modules
+.env
+coverage
+coverage.json
+typechain
+typechain-types
+
+# Hardhat files
+cache
+artifacts
+

6. Dapp/Live_Hhat_SSdap/backend/README.md

@@ -0,0 +1,13 @@
+# Sample Hardhat Project
+
+This project demonstrates a basic Hardhat use case. It comes with a sample contract, a test for that contract, and a script that deploys that contract.
+
+Try running some of the following tasks:
+
+```shell
+npx hardhat help
+npx hardhat test
+REPORT_GAS=true npx hardhat test
+npx hardhat node
+npx hardhat run scripts/deploy.js
+```

6. Dapp/Live_Hhat_SSdap/backend/contracts/Bank.sol

@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.20;
+
+error Bank__NotEnoughFundsProvided();
+error Bank__NotEnoughEthersOnTheSC();
+error Bank__WithdrawFailed();
+
+/// @title A simple wallet contract
+/// @author Ben BK
+/// @notice Allows to send and withdraw Ethers from a smart contract
+
+contract Bank {
+
+    mapping(address => uint) balances;
+
+    /// @notice Allows to send Ethers to the smart contract
+    function sendEthers() external payable {
+        if(msg.value < 1 wei) {
+            revert Bank__NotEnoughFundsProvided();
+        }
+        balances[msg.sender] += msg.value;
+    }
+
+    /// @notice Allows to withdraw Ethers from the smart contract
+    /// @param _amount The amount to withdraw
+    function withdraw(uint _amount) external {
+        if(_amount > balances[msg.sender]) {
+            revert Bank__NotEnoughEthersOnTheSC();
+        }
+        balances[msg.sender] -= _amount;
+        (bool received, ) = msg.sender.call{value: _amount}("");
+        if(!received) {
+            revert Bank__WithdrawFailed();
+        }
+    }
+}

6. Dapp/Live_Hhat_SSdap/backend/contracts/Lock.sol

@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.9;
+
+// Uncomment this line to use console.log
+// import "hardhat/console.sol";
+
+contract Lock {
+    uint public unlockTime;
+    address payable public owner;
+
+    event Withdrawal(uint amount, uint when);
+
+    constructor(uint _unlockTime) payable {
+        require(
+            block.timestamp < _unlockTime,
+            "Unlock time should be in the future"
+        );
+
+        unlockTime = _unlockTime;
+        owner = payable(msg.sender);
+    }
+
+    function withdraw() public {
+        // Uncomment this line, and the import of "hardhat/console.sol", to print a log in your terminal
+        // console.log("Unlock time is %o and block timestamp is %o", unlockTime, block.timestamp);
+
+        require(block.timestamp >= unlockTime, "You can't withdraw yet");
+        require(msg.sender == owner, "You aren't the owner");
+
+        emit Withdrawal(address(this).balance, block.timestamp);
+
+        owner.transfer(address(this).balance);
+    }
+}

6. Dapp/Live_Hhat_SSdap/backend/contracts/SimpleStorage.sol

@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.20;
+
+/// @title a simple storage contract
+/// @author Ben BK
+
+contract SimpleStorage {
+
+    uint private number;
+
+    /// @notice Set the number
+    /// @dev Nothing to say
+    /// @param _number the new number which will be in storage in the blockchain
+    function setNumber(uint _number) external {
+        number = _number;
+    }
+
+    /// @notice Get the number which is stored in the blockchain
+    /// @return Returns the number
+    function getNumber() external view returns(uint) {
+        return number;
+    }
+
+} 

6. Dapp/Live_Hhat_SSdap/backend/hardhat.config.js

@@ -0,0 +1,6 @@
+require("@nomicfoundation/hardhat-toolbox");
+
+/** @type import('hardhat/config').HardhatUserConfig */
+module.exports = {
+  solidity: "0.8.20",
+};