Data Structures with C++ using STL 2E Chapter 5.ppt

1、1,Pointer Illustration Vertical / Horizontal View . . . Data Addresses in Memory Declaring Pointer Variables Assigning Values to Pointers Accessing Data with Pointers Arrays and Pointers Operator new Operator delete Illustrating the Destructor Copy Constructor / Overloaded Assignment Operator Declar

2、ation of dynamicClass Objects,Chapter 5 Pointers and Dynamic Memory,The Pointer this dynamicClass Copy Constructor The C+ Index Operator Matrices Summary Slides (3 pages),2,Pointer Illustration,3,Vertical and Horizontal View of Memory,4,Data Addresses in Memory,5,Declare a pointer by stating the typ

3、e followed by the variable name, but with a * added immediately before the name. The pointer ptr is a variable whose value is the address of a data item of the designated type.,Declaring Pointer Variables,6,Assigning Values to Pointers,7,Accessing Data with Pointers,int x = 50, y = 100, *px = ,8,Arr

4、ays and Pointers,9,Operator new,p = new time24; / *p is 00:00 (midnight) q = new time24(8, 15); / *q is 8:15 AM,10,Operator delete,deallocating a dynamic array, use a slightly different form of delete. Place square brackets between delete and the pointer variable name. The system deallocates all of

5、the memory originally assigned to the dynamic array.,arr = new TARRSIZE; / allocated space for ARRSIZE objects delete arr; / deallocate dynamic array storage,11,Illustrating the Destructor,12,Copy Constructor / Overloaded Assignment Operator,13,Declaration of dynamicClass Objects,14,The Pointer this

6、,15,dynamicClass Copy Constructor Algorithm,16,The C+ Index Operator ,arri = 30;/ arri is the address into which 30 is copied t = arri + 4;/ add 4 to the value of the element at arri,17,Matrices,A Matrix is a two-dimensional array that corresponds to a row-column table of entries of a specified data

7、 type. Matrices are referenced using a pair of indices that specify the row and column location in the table.,Example: The element mat03 is 2 The element mat12 is 4.,18,Summary Slide 1,-Pointers contain the address of data in memory -Data is accessed by applying the dereference operator * - Operator

8、s such as +, +, and += apply to pointers. - With such operators, pointers can be used for algorithms involving array traversal, but their primary application is in the allocation and maintenance of dynamic memory.,19,Summary Slide 2,-vector implementation-The miniVector class illustrates the key poi

9、nts. 1)It allocates dynamic memory using: destructor copy constructor overloaded assignment operator 2)It implements push_back(): Therefore it must control vector capacity in orderto minimize dynamic memory reallocation. 3)It allows access to elements by using an index:Therefore the class implements an overloaded index operator,20,Summary Slide 3,-Two dimensional arrays in C+ -have the same problems as one-di