ISO C ++禁止声明无类型的“堆栈" [英] ISO C++ forbids declaration of 'Stack' with no type
问题描述
下面有一个用于堆栈结构的头文件.我不明白的是此错误正在干扰我:
I have below a header file for a stack structure. what I don't understand is this error it is jamming at me:
ISO C ++禁止声明无类型的'Stack'
ISO C++ forbids declaration of 'Stack' with no type
这是代码:
#include <stdexcept>
class Element;
class Stack{
public:
Stack():first(0){}; //constructor
~Stack(); //destructor
void push(int d);
int pop()throw(length_error);
bool empty();
private:
Element *first;
Stack(const& Stack){}; //copy constructor
Stack& operator = (const& Stack){}; //assignment operator..
};
有人知道错误是什么意思吗?
does anyone have a clue what the error means?
推荐答案
Stack&operator =(const& Stack)
应该是 Stack&运算符=(const Stack&)
.
您没有指向引用或引用数组的指针或任何其他内容,因此编译器认为&
必须终止声明的类型部分,并认为以下 Stack
必须是参数名称.但是 const&
中没有类型,因此编译器说您不能声明没有类型的参数 Stack
.在旧版本的C中,有时会在可能出现某种类型但又忽略了某种类型的上下文中推断出 int
类型,这就是为什么该错误谈到ISO C ++禁止这种情况的原因.
You can't have a pointer to a reference or an array of references or anything so the compiler thinks that &
must end the type part of the declaration and that the following Stack
must be the parameter name. However there's no type in const&
so the compiler says that you can't declare the parameter Stack
with no type. In old versions of C the type int
was sometimes inferred in contexts where a type could appear but was omitted which is why the error talks about ISO C++ forbidding this.
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