Pointers Applications of Computer Programming in Earth Sciences Instructor: Dr. Cheng-Chien LiuCheng-Chien Liu Department of Earth Sciences National Cheng Kung University Last updated: 2 November 2004 Chapter 8

Introduction  Pointer A variable that holds a memory address Ex 8-1 “Address of” operator &  Convention of naming  Declaration Indirection (dereference) operator *  提領（取出指標所指物體的內容）  The value stored at …  Initialization Wild pointer  dangerous  Pointers  addresses  variables Manipulating data: Ex 8-2 Examining the address: Ex 8-3

Why use pointers  Three tasks of using pointers Managing data on the free store Accessing class member data and functions Passing variables by reference to functions  Five areas of memory Global name space  global variables The free store  heap  all remaining memory Registers  internal housekeeping Code space  code The stack  local variables, function parameters  Concept of free store

Using free store  Advantages of free store Solves the problem of global and local variable Remains available until you explicitly free it Only functions with access to the pointer  tightly controlled interface  How to use the free store new delete Ex 8-4 Ex 8-5: applying to object  Memory leak

Using free store (cont.)  Access member data of objects dot operator “.” points-to operator “->” Ex 8-6 Ex 8-7  Stray pointers Ex 8-9  const pointers Ex 8-10