我有一个从Array class
继承的BaseArray class
。在BaseArray
中,我具有受保护的成员变量data_
和cur_size_
。 Array
类引入了resize
函数。我遇到的问题是,在BaseArray
函数中似乎没有访问resize
中受保护的成员变量。
编辑:解决了max_size_
问题,但cur_size_
和data_
文件仍然存在
遗产?范围?救命?
错误:
In file included from Array.h:41:0,
from driver.cpp:6:
Array.cpp: In member function ‘void Array<T>::resize(size_t)’:
Array.cpp:29:5: error: ‘data_’ was not declared in this scope
data_=data_;
^
Array.cpp:30:18: error: ‘cur_size_’ was not declared in this scope
if (new_size>cur_size_)
^
Array.cpp:37:5: error: ‘cur_size_’ was not declared in this scope
cur_size_=new_size;
^
代码:
BaseArray.h:
#ifndef _BASEARRAY_H_
#define _BASEARRAY_H_
#include <cstring>
template <typename T>
class BaseArray
{
public:
/// Type definition of the element type.
typedef T type;
//constructors, destructor and methods…
protected:
/// Pointer to the actual data. m
char * data_;
/// Current size of the BaseArray.
size_t cur_size_;
};
#include "BaseArray.inl"
#include "BaseArray.cpp"
#endif // !defined _BASEARRAY_H_
Array.h:
#ifndef _ARRAY_H_
#define _ARRAY_H_
#include <cstring>
#include "BaseArray.h"
template <typename T>
class Array: public BaseArray<T> //inheriting from BaseArray
{
public:
/// Type definition of the element type.
typedef T type;
/// Default constructor.
Array (void);
Array (const Array & arr);
/// Destructor.
~Array (void);
const Array & operator = (const Array & rhs);
void resize (size_t new_size);
private:
size_t max_size_; //introduces max_size
};
#include "Array.inl"
#include "Array.cpp"
#endif // !defined _ARRAY_H_
Array.cpp:
#include "BaseArray.h"
#include "Array.h"
#include <stdexcept>
#include <iostream>
template <typename T>
Array <T>::Array (void): BaseArray<T>()
{
std::cout<<"Array def const called"<<std::endl;
}
template <typename T>
Array <T>::Array (const Array & array): BaseArray<T>(array)
{
}
template <typename T>
Array <T>::~Array (void)
{
}
template <typename T>
void Array <T>::resize (size_t new_size)
{
this->data_= this->data_;
if (new_size>this->cur_size_)
{
max_size_ = new_size-this->cur_size_-1;
this->cur_size_=new_size;
for (max_size_; max_size_<=new_size; max_size_++)
this->data_[max_size_]=0;
}
this->cur_size_=new_size;
}
/* Also tried it like this:
template <typename T>
void Array <T>::resize (size_t new_size)
{
BaseArray<T>::data_= BaseArray<T>::data_;
if (new_size>BaseArray<T>::cur_size_)
{
max_size_ = new_size-BaseArray<T>::cur_size_-1;
BaseArray<T>::cur_size_=new_size;
for (max_size_; max_size_<=new_size; max_size_++)
BaseArray<T>::data_[max_size_]=0;
}
BaseArray<T>::cur_size_=new_size;
} */
最佳答案
关于第一个错误,您在Array中没有声明max_size()成员。
关于第二个错误,模板中的名称查找遵循两步逻辑,即在定义点查找非从属表达式,而在实例化点查找从属表达式;
这意味着当编译器看到data_
时,它会认为这是一个位于其他位置的变量。充其量,它不会给您带来错误,最糟糕的是,它会给您带来错误的变量!
为了解决该问题,您需要使它成为一个依赖表达式,最明显的方法是用data_
替换所有this->data_
等。
关于代码组织,将模板定义到单个头文件中;如果您真的想拆分成员实现,请将其放在具有合理文件扩展名的单个文件中(inl可以,cpp不能)...