Blockchain By Example

Contract destruction

At this final step, let's have some fun.

What about introducing a nuclear launch button in our contract that, once pushed by the auction owner, will make the contract disappear from the blockchain? The contract destruction will be ensured by the destruct_auction() method, which can be invoked if all participants have withdrawn their bids, as follows:

function destruct_auction() external only_owner returns (bool) {    require(now > auction_end, "You can't destruct the contract,The auction is still open");    for (uint i = 0; i < bidders.length; i++)    {        assert(bids[bidders[i]] == 0);    }    selfdestruct(auction_owner);    return true;}

The first thing that we can see here is that Solidity defines for-loops like standard languages, and ...