C++类 单冒号

1.继承

class Base { };

class Derived : public Base { };

示列:

  class Base
  {
　　　public:
　　　int a=10;
  };

  class Derived : public Base
  {

  };

  int main()
  {
　　　Derived b;
　　　cout<<b.a<<endl;
  }

2.访问控制

class MyClass {
public:
    void public_member() { }
private:
    void private_member() { }
};

3.列表初始化

class MyClass {
private:
    int member;
public:
    MyClass() : member(0) { }
};

4.位域

class MyClass {
public:
    unsigned first : 1;
    unsigned second : 2;
    unsigned third : 4;
};