In short words, yes you can copy and paste Bitcoin code and you may run your own altcoin. Just keep in mind it will call altcoin, not Bitcoin. Its because the chain will be totally different from Bitcoin, it does not have any relationship with the current Bitcoin blockchain. As you are asking about the BCH address, the best explanation has been given here, Why do Bitcoin Cash addresses look different from Bitcoin addresses? . They have added a new format of the address called CashAddr.