![Проблема “одинаковых классов”
struct ArrayInt {
explicit ArrayInt(size_t size)
: data_(new int[size ])
, size_(size) {}
~ArrayInt () {delete [] data_ ;}
size_t size () const
{ return size_; }
int operator []( size_t i) const
{ return data_[i]; }
int & operator []( size_t i)
{ return data_[i]; }
...
private:
int * data_;
size_t size_;
};
struct ArrayFlt {
explicit ArrayFlt(size_t size)
: data_(new float[size ])
, size_(size) {}
~ArrayFlt () {delete [] data_ ;}
size_t size () const
{ return size_; }
float operator []( size_t i) const
{ return data_[i]; }
float & operator []( size_t i)
{ return data_[i]; }
...
private:
float * data_;
size_t size_;
};
2/5](https://image.slidesharecdn.com/6-151030211140-lva1-app6892/85/6-1-2-320.jpg)
![Решение в стиле C: макросы
#define DEFINE_ARRAY (Name , Type )
struct Name {
explicit Name(size_t size)
: data_(new Type[size ])
, size_(size) {}
~Name () { delete [] data_; }
size_t size () const
{ return size_; }
Type operator []( size_t i) const
{ return data_[i]; }
Type & operator []( size_t i)
{ return data_[i]; }
...
private:
Type * data_;
size_t size_;
}
DEFINE_ARRAY (ArrayInt , int);
DEFINE_ARRAY (ArrayFlt , float );
int main ()
{
ArrayInt ai (10);
ArrayFlt af (20);
...
return 0;
}
3/5](https://image.slidesharecdn.com/6-151030211140-lva1-app6892/85/6-1-3-320.jpg)
![Решение в стиле C++: шаблоны классов
template <class Type >
struct Array {
explicit Array(size_t size)
: data_(new Type[size ])
, size_(size) {}
~Array ()
{ delete [] data_; }
size_t size () const
{ return size_; }
Type operator []( size_t i) const
{ return data_[i]; }
Type & operator []( size_t i)
{ return data_[i]; }
...
private:
Type * data_;
size_t size_;
};
int main ()
{
Array <int > ai (10);
Array <float > af (20);
...
return 0;
}
4/5](https://image.slidesharecdn.com/6-151030211140-lva1-app6892/85/6-1-4-320.jpg)
![Шаблоны классов с несколькими параметрами
template <class Type ,
class SizeT = size_t ,
class CRet = Type >
struct Array {
explicit Array(SizeT size)
: data_(new Type[size ])
, size_(size) {}
~Array () {delete [] data_ ;}
SizeT size () const {return size_ ;}
CRet operator []( SizeT i) const
{ return data_[i]; }
Type & operator []( SizeT i)
{ return data_[i]; }
...
private:
Type * data_;
SizeT size_;
};
void foo ()
{
Array <int > ai (10);
Array <float > af (20);
Array <Array <int >,
size_t ,
Array <int > const&>
da (30);
...
}
typedef Array <int > Ints;
typedef Array <Ints , size_t ,
Ints const &> IInts;
void bar ()
{
IInts da (30);
}
5/5](https://image.slidesharecdn.com/6-151030211140-lva1-app6892/85/6-1-5-320.jpg)
6.1 Шаблоны классов
- 1. Программирование на языке C++ Лекция 6 Шаблоны классов Александр Смаль 1/5
- 2. Проблема “одинаковых классов” struct ArrayInt { explicit ArrayInt(size_t size) : data_(new int[size ]) , size_(size) {} ~ArrayInt () {delete [] data_ ;} size_t size () const { return size_; } int operator []( size_t i) const { return data_[i]; } int & operator []( size_t i) { return data_[i]; } ... private: int * data_; size_t size_; }; struct ArrayFlt { explicit ArrayFlt(size_t size) : data_(new float[size ]) , size_(size) {} ~ArrayFlt () {delete [] data_ ;} size_t size () const { return size_; } float operator []( size_t i) const { return data_[i]; } float & operator []( size_t i) { return data_[i]; } ... private: float * data_; size_t size_; }; 2/5
- 3. Решение в стиле C: макросы #define DEFINE_ARRAY (Name , Type ) struct Name { explicit Name(size_t size) : data_(new Type[size ]) , size_(size) {} ~Name () { delete [] data_; } size_t size () const { return size_; } Type operator []( size_t i) const { return data_[i]; } Type & operator []( size_t i) { return data_[i]; } ... private: Type * data_; size_t size_; } DEFINE_ARRAY (ArrayInt , int); DEFINE_ARRAY (ArrayFlt , float ); int main () { ArrayInt ai (10); ArrayFlt af (20); ... return 0; } 3/5
- 4. Решение в стиле C++: шаблоны классов template <class Type > struct Array { explicit Array(size_t size) : data_(new Type[size ]) , size_(size) {} ~Array () { delete [] data_; } size_t size () const { return size_; } Type operator []( size_t i) const { return data_[i]; } Type & operator []( size_t i) { return data_[i]; } ... private: Type * data_; size_t size_; }; int main () { Array <int > ai (10); Array <float > af (20); ... return 0; } 4/5
- 5. Шаблоны классов с несколькими параметрами template <class Type , class SizeT = size_t , class CRet = Type > struct Array { explicit Array(SizeT size) : data_(new Type[size ]) , size_(size) {} ~Array () {delete [] data_ ;} SizeT size () const {return size_ ;} CRet operator []( SizeT i) const { return data_[i]; } Type & operator []( SizeT i) { return data_[i]; } ... private: Type * data_; SizeT size_; }; void foo () { Array <int > ai (10); Array <float > af (20); Array <Array <int >, size_t , Array <int > const&> da (30); ... } typedef Array <int > Ints; typedef Array <Ints , size_t , Ints const &> IInts; void bar () { IInts da (30); } 5/5