Download Object-Oriented Programming: Templates, Static Members, and Generic Algorithms and more Slides Object Oriented Programming in PDF only on Docsity! Object-Oriented Programming (OOP) Lecture No. 39 Templates & Static Members ►Each instantiation of a class template has its own copy of static members ►These are usually initialized at file scope docsity.com …Templates & Static Members template< class T > class A { public: static int data; static void doSomething( T & ); }; …Templates & Static Members int main() { A< int > ia; A< char > ca; ia.data = 5; ca.data = 7; cout << “ia.data = ” << ia.data << endl << “ca.data = ” << ca.data; return 0; } docsity.com Generic Algorithms Revisited template< typename P, typename T > P find( P start, P beyond, const T& x ) { while ( start != beyond && *start != x ) ++start; return start; } …Generic Algorithms Revisited int main() { int iArray[5]; iArray[0] = 15; iArray[1] = 7; iArray[2] = 987; … int* found; found = find(iArray, iArray + 5, 7); return 0; } docsity.com …Generic Algorithms Revisited ►We claimed that this algorithm is generic ►Because it works for any aggregate object (container) that defines following three operations Increment operator (++) Dereferencing operator (*) Inequality operator (!=) …Generic Algorithms Revisited ►Let us implement these operations in Vector to examine the generality of the algorithm ►Besides these operations we need a kind of pointer to track the traversal docsity.com Example – Vector template< class T > class Vector { private: T* ptr; int size; int index; // initialized with zero public: … Vector( int = 10 ); …Example – Vector Vector( const Vector< T >& ); T& operator [](int); int getIndex() const; void setIndex( int i ); T& operator *(); bool operator !=( const Vector< T >& v ); Vector< T >& operator ++(); }; docsity.com …Example – Vector int main() { Vector<int> iv( 3 ); iv[0] = 10; iv[1] = 20; iv[2] = 30; Vector<int> beyond( iv ),found( 3 ); beyond.setIndex( iv.getSize() ); found = find( iv, beyond, 20 ); cout<<“Index: ”<<found.getIndex(); return 0; } Generic Algorithm template< typename P, typename T > P find( P start, P beyond, const T& x ) { while ( start != beyond && *start != x ) ++start; return start; } docsity.com Problems ►Our generic algorithm now works fine with container Vector ►However there are some problems with the iteration approach provided by class Vector …Problems ►No support for multiple traversals ►Inconsistent behavior We use pointers to mark a position in a data structure of some primitive type Here we use the whole container as marker e.g. found in the main program ►Supports only a single traversal strategy docsity.com
