Question

i 有问题。我有一个类逻辑, 有字符串和对象。我希望在逻辑类中写入 < code> cout & lt; a 时, 这个运算符会更改我的字符串。所以我这样做 :

逻辑h

class logic
{
private:
int str;
A a;
public:
...
};

逻辑学.cpp

...
...
cout<<*a;
...

ostream& operator<<(ostream& os, const A& A)
{
    int=a.num;
    return os;
}

z.h 小时

class Z
{
public:
virtual Z* aa();
...
};

a.h (小时)

class A: public Z
{
private:
int num;
public:
virtual Z* aa();
...
};

我犯了这些错误:

expected class-name before { token (on class A:public Z { ) ISO C++ forbids declaration of Z with no type, Z declared as a virtual field, expected ; before * token (on every virtual function in A)

你能帮我吗?

Answer 1

类定义后需要分号 :

class A: public Z
{
private:
  int num;
  public:
  virtual Z* aa();
  // ...
}; // <-- SEMICOLON!!1

另外,确保被定义为 before A A , z.h in a.h 。

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