Lottery smart contract (Solidity)

Solidity/examples/lottery.sol

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+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.17;
+
+contract Lottery {
+    address public manager;
+    address payable[] public players;
+
+    constructor() {
+        manager = msg.sender;
+    }
+
+    function alreadyEntered() private view returns (bool) {
+        for (uint i = 0; i < players.length; i++) {
+            if (players[i] == msg.sender) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    function enter() public payable {
+        require(msg.sender != manager, "Manager cannot enter");
+        require(!alreadyEntered(), "Player already entered");
+        require(msg.value >= 1 ether, "Minimum amount must be paid");
+        players.push(payable(msg.sender));
+    }
+
+    function random() private view returns (uint) {
+        return uint(keccak256(abi.encodePacked(block.prevrandao, block.timestamp, players)));
+    }
+
+    function pickWinner() public {
+        require(msg.sender == manager, "Only Manager can pick the winner");
+        require(players.length > 0, "No players in the lottery");
+        uint index = random() % players.length;
+        players[index].transfer(address(this).balance);
+        players = new address payable[](0);
+    }
+
+    function getPlayers() public view returns (address payable[] memory) {
+        return players;
+    }
+}