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On completion of this chapter students will know how to: Function templates; class templates; three types of sequences containers are vector, deque and list; basic components of STL are iterators, algorithms and containers; STL has both sequence and associative containers.
Chapter 17 – Templates Function Templates Express general form for a function Example: template for adding two numbers template Type sum (Type a, Type b) { return (a + b); } Lesson 17.1 Function Templates Called in same manner as ordinary function Permissible to have both generic data types and ordinary data types Treated similar to overloaded function Need to be careful that function call data types compatible with function bodies Useful for operations that apply to many data types Lesson 17.1 Overloaded Function Templates Cannot replace overloaded functions Perform same operations for each different data type Can vary number of arguments Specify more than one type of argument – Distinguished by number or distribution of types of arguments Lesson 17.1 Class Templates: Example template class Class1 Name of class { private: Type value; Data member public: Class1 ( ); Constructor void set_value (Type); Member functions Type get_value ( ); }; Lesson 17.2 Class Template Allows creation of object of class and use the data type of choice Syntax to declare object – Class1 ob; – Indicates the ob.value is type double Lesson 17.2 Mechanics of Class Templates Declaration for object using class template – Causes memory reserved for all data members – Causes instructions to be generated and stored for all function members If another object with same bracketed data type declared – New memory reserved, but no new function instructions Lesson 17.2 Friends of Class Templates Four cases (assuming single type parameter) – Ordinary function friend of each template class instantiated from class template – Ordinary class friend of each template class instantiated from class template – Template function – only if type parameter for function and class same – Template class – only matching type class is friend Lesson 17.2 Standard Template Library Sequence Containers Designed to directly control position of element within container Three containers – vector – deque – list Dynamic memory allocation used to reserve memory Lesson 17.3 Vectors Need to include header vector vector1; – Declares vector1 to be vector container of int Elements in contiguous memory locations – First element has subscript 0 Can be accessed using arraylike notation – “push” family of functions reserve memory and initialize single element Random access Lesson 17.3 Deques Need to include header deque deque1; – Declares deque1 to be deque container of char Can be created using push_front( ) and push_back ( ) Elements in contiguous memory locations Can modify values with array notation – First element, subscript 0 Random Access Lesson 17.3 Lists Need to include the header list list1; – Declares list1 to be list container of doubles Called doubly linked list – Two pointer values: one to next element and another to previous element Not stored in contiguous memory Lesson 17.3 Standard Template Library Iterators Designed to be userfriendly pointers – Know type of container Can go through list with ++ operator General form for declaring container :: iterator name; ordinary iterator needs no special header file Lesson 17.4 Using an Iterator Need to initialize to point to location first then manipulate begin ( ) member function returns object that points to memory location of first element Can access element pointed to by iterator using unary * operator Lesson 17.4 Constant Iterators General form or declaring container :: const_iterator name; Type of container such as list, vector or deque Valid identifier for iterator Data type of container Lesson 17.4 List Iterators and Operators Called bidirectional iterators Cannot advance more than one element at a time Use both ++ and to more forward and backward in list Useable operators – unary * operator, ++, , =, ==, and != Lesson 17.4 Standard Template Library Algorithms Different definition than dictionary Global template functions designed to work with containers using iterators Not member functions called with function name and argument list name (iterator1, iterator2, iterator3); – name is name of algorithm – iterator1, iterator2, iterator3 names of iterators or return values from member functions Lesson 17.5 Summary Function templates Class templates Three types of sequences containers are vector, deque and list Basic components of STL are iterators, algorithms and containers STL has both sequence and associative containers ... New memory reserved, but no new function instructions Lesson 17.2 Friends of Class Templates Four cases (assuming single type parameter) – Ordinary function friend of each template class instantiated from class template – Ordinary class friend of each template class ... General form for declaring container :: iterator name; ordinary iterator needs no special header file Lesson 17.4 Using an Iterator Need to initialize to point to location first then manipulate begin ( ) member function returns object that ... Dynamic memory allocation used to reserve memory Lesson 17.3 Vectors Need to include header vector vector1; – Declares vector1 to be vector container of int Elements in contiguous memory locations – First element has subscript 0