Pointers Presentation

crashclappergapSoftware and s/w Development

Dec 13, 2013 (3 years and 8 months ago)

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Pointers

By Sarah Gates

Starter Task


Short Discussion:


Emison


Pointers


Glenn


Hexadecimal numbers


What do you remember about them?


What was the defining points you remember
from those sessions?

Learning Objectives


Know the 2 different types of data structure
(Dynamic and Static)


Know what a pointer is in Programming and
where they are used.


Identify different types of pointers, and
understand why these different types are
needed.



First things first…


Data structure


A collection of data stored in memory, plus a number of
operations included by the software to manipulate the
data structure (Definition found on Teach ICT website
http://www.teach
-
ict.com/as_as_computing/ocr/H447/F453/3_3_5/dat
a_structures/miniweb/pg2.htm
)


Different types of Data structure


Dynamic (Stack) Where memory is allocated at the point
of run time.


Static (List) memory is allocated at the time the
structure is compiled and is fixed.



Pointers


Sometimes called “references” (e.g. in Perl…)


A variable which “points” to a location in the
memory of a computer.


Usually points to an address (numbered location of a
place in the memory),


Used in almost all programming languages including C,
C++, Pascal, Perl, and BASIC.


Different types of pointers


Managed


Unmanaged function pointers


Stack


An example

Cont


Address locations given in Hexadecimal
numbers


int

*
hardware_address

= (
int

*)0x7FFF;


an example of a pointer initialising to a
hexidecimal

address.


http://www.youtube.com/watch?v=f
-
pJlnpkLp0


A fun little video about pointers and
pointees

Finally: taken from
http://xkcd.com/138/