// SPDX-License-Identifier: MIT pragma solidity 0.8.20; contract Lottery{ address public manager; address payable[] public participant;

constructor(){
    manager = msg.sender;
}
receive() external payable {
    require(msg.value==1 ether);
    participant.push(payable(msg.sender));
}

function getBalance() public view returns(uint){
    require(msg.sender == manager);
    return address(this).balance;
}
function random() public view returns (uint) {

return uint(keccak256(abi.encodePacked(blockhash(block.number - 1), block.timestamp, participant.length))); }

function selectWinner() public { require(msg.sender==manager); require(participant.length>=3); uint r = random(); address payable winner; uint index = r%participant.length; winner=participant[index]; winner.transfer(getBalance()); participant = new address payable; }

}