繼承是C++語言的三大特點之一。繼承(或者說派生)機制的作用主要是用於代碼的重用和擴展。
三種派生方式(public,protect,private)的訪問控制
基類的控制類型 派生方式 派生類的控制類型
public ········································public
protect ··················public protect
private ——
public ··········································protect
protect··················· protect protect
private ············································ ——
public ·····private
protect ····················private private
private ——
上面列出了不同派生方式得到的派生類有着不同的訪問控制情況。比如,基類的public成員經過protect方式的派生,在派生類中會變成protect成員,即派生類成員可以訪問該成員,而類外的派生類對象不能訪問它,以此類推。