繼承子類時的默認保護級別是什麼？

Question

可能重複：
Default class inheritance access

我知道我可以設置保護級別，當我宣佈從超類的子類，如：

class Dog : public Pet { 
    *blah, blah, blah* 
} 

但什麼是該在這種情況下保護級別默認爲？

Class Dog: Pet { 
    *blah, blah, blah* 
} 

Answer 1

對於一類是私人

class Dog: Pet // Pet is inherited privately. 
{} 

對於一個結構它是公共的。

struct Dog: Pet // Pet is inherited publicly. 
{} 

簡單的測試：

class Pet {}; 
class DogClass: Pet {}; 
struct DogStruct: Pet {}; 
int main() 
{ 
    DogClass dogClass; 
    // Pet&  pet1 = dogClass; This line will not compile. 

    DogStruct dogStruct; 
    Pet&  pet2 = dogStruct; 
}