C++: Vector bounds

Question

I am coming from Java and learning C++ in the moment. I am using Stroustrup\'s Progamming Principles and Practice of Using C++. I am working with vectors now. On page 117 he

Answer 1

I hoped that vector's "operator[]" would check boundary as "at()" does, because I'm not so careful. :-)

One way would inherit vector class and override operator[] to call at() so that one can use more readable "[]" and no need to replace all "[]" to "at()". You can also define the inherited vector (ex:safer_vector) as normal vector. The code will be like this(in C++11, llvm3.5 of Xcode 5).

#include 

using namespace std;

template  >
class safer_vector:public vector<_Tp, _Allocator>{
private:
    typedef __vector_base<_Tp, _Allocator>           __base;
public:
    typedef _Tp                                      value_type;
    typedef _Allocator                               allocator_type;
    typedef typename __base::reference               reference;
    typedef typename __base::const_reference         const_reference;
    typedef typename __base::size_type               size_type;
public:

    reference operator[](size_type __n){
        return this->at(__n);
    };

    safer_vector(_Tp val):vector<_Tp, _Allocator>(val){;};
    safer_vector(_Tp val, const_reference __x):vector<_Tp, _Allocator>(val,__x){;};
    safer_vector(initializer_list __il):vector<_Tp, _Allocator>(__il){;}
    template 
    safer_vector(_Iterator __first, _Iterator __last):vector<_Tp,_Allocator>(__first, __last){;};
    // If C++11 Constructor inheritence is supported
    // using vector<_Tp, _Allocator>::vector;
};
#define safer_vector vector