[英]Accessing member variables from aggregated class
Just trying to get stack.cpp
's push function to increment max_size_
variable by 1.只是试图让
stack.cpp
的推送函数将max_size_
变量增加 1。
Array.h:数组.h:
template <typename T>
class Array: public BaseArray<T>
{
public:
//loads of fun code
private:
size_t max_size_;
};
Stack.cpp:堆栈.cpp:
//...even more fun code...
template <typename T>
void Stack <T>::push (T element)
{
ArrayStack::max_size_++;
}
Stack.h:堆栈.h:
template <typename T>
class Stack
{
public:
Stack (void);
private:
Array <T> ArrayStack;
};
Error:错误:
error: ‘ArrayStack’ is not a class or namespace
ArrayStack::max_size_++;
Or if I run it with just max_size_
:或者,如果我只使用
max_size_
运行它:
template <typename T>
void Stack <T>::push (T element)
{
max_size_++;
}
error: ‘max_size_’ was not declared in this scope
max_size_++;
You actually can't do that without changing something.你实际上不能不改变一些东西来做到这一点。
max_size_++;
is a private member of ArrayStack
, so you cannot change it from inside a Stack
method.是
ArrayStack
的私有成员,因此您不能从Stack
方法内部更改它。
Option 1 (better): Add a method to your ArrayStack
that increments the value by one void incMaxSize() { max_size_++; }
选项 1(更好):向您的
ArrayStack
添加一个方法,该方法将值增加一个void incMaxSize() { max_size_++; }
void incMaxSize() { max_size_++; }
and call it instead void incMaxSize() { max_size_++; }
并调用它,而不是
Option 2 (worse): Make the Stack
class a friend of ArrayStack
选项 2(更糟):让
Stack
类成为ArrayStack
的朋友
Option 3 (even worse): Make the max_size_
variable public and then change the call to ArrayStack.max_size_++;
选项 3(甚至更糟):公开
max_size_
变量,然后将调用更改为ArrayStack.max_size_++;
Since you made max_size_ private in your Array class you'll need to create a getter and setter to access it outside of that class.由于您在 Array 类中将 max_size_ 设为私有,因此您需要创建一个 getter 和 setter 以在该类之外访问它。 Then in your Stack class you can get the max_size_ value and save it in a local variable and then set it to 1 + it's current value to achieve max_size_++
然后在您的 Stack 类中,您可以获得 max_size_ 值并将其保存在局部变量中,然后将其设置为 1 + 它的当前值以实现 max_size_++
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