Requesting ether via a contract

Question

I'm trying to create a smart contract for a basic raffle system where the user deposits funds to the contract and then a user is picked and the winner is sent the ether from the contract, I've got everything working apart from invoking a request to the user to deposit Ether to the contract and am wondering how I would perform this.

In short, I'm trying to create a function whereby the user can enter a number of Ether that they to deposit and the contract will accept it.

Thanks

Answer 1

See https://programtheblockchain.com/posts/2017/12/15/writing-a-contract-that-handles-ether/. In particular, you need the payable modifier on the function. For example:

function buyTicket() payable public {
    // In here, msg.value is the amount, in ether, that was sent