Page 256 - DCAP404 _Object Oriented Programming

Unit 11: Pointers and Dynamic Memory Management

Notes
instantiate the object. From the client’s perspective, the object already exists and calls can
be made to it without the need to create or initialise the object. This is the default behaviour
of SOAP-based Web services.
Digest authentication does not transfer the user’s password in the clear; instead a hash, or
digest, of the password and data provided by the server is used to authenticate the user.

From a developer’s perspective, .NET My Services eliminates many of the problems of
securing data, providing encrypted transport channels, and reconciling disparate data
sources. And all of this is achievable using XML Web services, so businesses are spared the
drastic learning curve associated with new technologies.
Remember, they say Web services are the next big thing.
From OOP to more

LET us say you already understand OOP (object-oriented programming) concepts such as
data abstraction, inheritance and polymorphism. And that you want to ‘leverage the
power of .NET Framework to build, package and deploy any kind of application’. Jeffrey
Richter’s “Applied Microsoft .NET Framework Programming” has the answers. Read on:

As an application runs, the common language runtime (CLR) maintains a ‘snapshot’ of the
set of assemblies loaded by the application. When the application terminates, this
information is compared with the information in the application’s corresponding .ini file.
If the application loaded the same set of assemblies that it loaded previously, the
information in the .ini file matches the information in memory and the in memory
information is discarded.
Sometimes the add and remove methods the compiler generates are not ideal. For example,
if you’re adding and removing delegates frequently and you know that your application
is single-threaded, the overhead of synchronising access to the object that owns the delegate
can really hurt your application’s performance.
Compilers convert code that references an enumerated type’s symbol to a numeric value
at compile time. Once this occurs, no reference to the enumerated type exists in metadata
and the assembly that defines the enumerated type doesn’t have to be available at run
time. If you have cod that references the enumerated type - rather than just having references
to symbols defined by the type - the assembly that defines the enumerated type will be
required at run time.
A try block doesn’t have to have a finally block associated with it at all; sometimes the
code in a try block just doesn’t require any cleanup code. However, if you do have a finally
block, it must appear after any and all catch blocks, and a try block can have no more than
one finally block associated with it.
If the CLR suspends a thread and detects that the thread is executing unmanaged code, the
thread’s return address is hijacked and the thread is allowed to resume execution. A
pinned object is one that the garbage collector isn’t allowed to move in memory.
11.6 Summary

 A pointer is a variable that holds the memory address of the location of another variable
in memory. A pointer is declared in the following form:

type * var_name ;
where type is a predefined C++ data type and var_name is the name of the pointer variable.

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