我正在尝试在C ++中重新创建vector类
我在();
的函数中得到了这个错误'int&'类型的非const引用的无效初始化来自临时的'int *'
类型即使函数应该返回引用,是不是可以将指针作为地址返回?
代码如下:
template<typename T>
class Vector
{
public:
explicit Vector(int initSize = 0);
Vector(const Vector & rhs) throw (std::bad_alloc);
~Vector();
const Vector & operator=(const Vector & rhs) throw (std::bad_alloc);
void resize(int newSize);
void reserve(unsigned int newCapacity);
bool empty() const;
int size() const;
int capacity() const;
T & operator[](int index);
const T & operator[](int index) const;
T & at(int index) throw (std::out_of_range);
void push_back(const T & x) throw (std::bad_alloc);
T pop_back();
const T & back() const;
typedef T * iterator;
typedef const T * const_iterator;
iterator insert(iterator it, const T& x) throw (std::bad_alloc);
iterator begin();
const_iterator begin() const;
iterator end();
const_iterator end() const;
private:
int theSize;
unsigned int theCapacity;
T * objects;
};
#include "vector.hpp"
#endif /* VECTOR_HPP_ */
template<typename T>
Vector<T>::Vector(int initSize):theSize
(initSize),theCapacity(128),objects(0)
{
}
typename Vector<T>::iterator Vector<T>::begin()
{
return objects;
}
template<typename T>
T & Vector<T>::at(int index) throw (std::out_of_range)
{
//if (index<=theSize)
return (begin()+index);
}
int main()
{
Vector<int>* vec1=new Vector<int>(4);
cout<<vec1->at(2)<<endl;
return 0;
}
答案 0 :(得分:2)
表达式begin()+index
是指针类型;你需要添加一个解引用来使它成为一个参考:
template<typename T>
T & Vector<T>::at(int index) throw (std::out_of_range)
{
return *(begin()+index);
}
请注意,这可能不安全,因为重新分配objects
的操作会使通过at()
函数获得的引用无效。