小编hcw*_*wil的帖子

这可能是我错过的一个简单错误，但我一生都无法弄清楚如何在这个合同中设置 msg.value 变量。我在网上读到这个值是与交易相关的 wei 数量，但是作为合约的调用者，我如何具体设置该值。这是我正在努力处理的合同。

杂注坚固性 0.8.7；

合同自动售货机 {

// Declare state variables of the contract
address public owner;
mapping (address => uint) public cupcakeBalances;

// When 'VendingMachine' contract is deployed:
// 1. set the deploying address as the owner of the contract
// 2. set the deployed smart contract's cupcake balance to 100
constructor() {
    owner = msg.sender;
    cupcakeBalances[address(this)] = 100;
}

// Allow the owner to increase the smart contract's cupcake balance
function refill(uint amount) public {
    require(msg.sender …