Create Casino.sol

Casino.sol

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+// SPDX-License-Identifier: MIT
+// Load in remix: remix.loadurl("https://github.com/web3examples/ethereum/solidity_examples/Casino.sol")
+// Carefull with gas-estimates: due to random this doesn''t allways work
+pragma solidity >=0.7.0 <0.9.0;
+
+/// @author Gerard Persoon
+/// @title A simple casino
+contract Casino {
+
+    event Won(bool win)  ;   // declaring event  
+
+    /// @notice Setup an intial amount for the bank, supplied during the creation of the contract.    
+    constructor() payable {
+    }
+
+    /// @notice Perform the bet and pay out if you win
+    /// @dev several temporary variables are created to make debugging easier
+    function betAndWin() public payable returns (bool) { // returning value isn't easy to retreive
+        address payable betPlacer = payable(msg.sender);
+        uint bet = msg.value;
+        uint payout = bet * 2;
+        uint balance = getBankBalance();    
+        require(bet > 0, "No money added to bet.");
+        require(payout <= balance, "Not enough money in bank for this bet."); // bet has already been added to bank balance
+        bool win = bool (getRandom()%2 == 0);
+        if (win) {
+            (bool success, /* bytes memory response*/) = betPlacer.call{value: payout}('');
+            require(success, "Pay was not successful.");
+        }
+        emit Won(win);// logging event
+        return win;
+    }
+
+    ///  @notice Check the balance of the bank
+    ///  @return returns the balance
+    function getBankBalance() public view returns(uint256) {
+        return address(this).balance;
+    }
+
+    /// @notice Draw a random number
+    /// @dev this is not secure but only to demonstrate
+    /// @return a pseudo random number
+    function getRandom() public view returns(uint256) { 
+        return uint256(keccak256(abi.encodePacked(block.difficulty, block.coinbase, block.timestamp)));  
+    }    
+
+    /// @notice Deposit more funds for bank
+    /// @dev used when the bank runs out of money
+    receive() external payable { 
+    }
+}