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Linked lists

ü Collections of data items lined up in a row

ü Dynamic, can grow and shrink at execute time.

ü Used pointers for manipulations.

ü Insertions and deletions in linked list.

Function used in Dynamic Memory allocation:

ü Malloc-take as a argument the number of byte to be allocated.

ü -if no memory is available a NULL is returned

ü newPtr=malloc(sizeof(struct node)

ü Free –de-allocated memory so that it can be used in the future.

ü -free(newptr)

ü Sizeof

Basic Function

ü Init- to initiallise the linked list

ü Insert –add a new data element to the linked list

ü Delete – remove an existing data

ü IsEmpty –determines if the linked list is empty.

ü Display-display the data in the linked list.

Stacks

ü A stacks is constrained version of the a link list.

ü Addition and deletion of nodes is at the top of the stack.

ü It is last-in-first out (LIFO) data structure.

ü A stack is referenced via a pointer to the top element of the stack.

ü Contain one and more data member.

ü Contain a pointer member. (refer to first node)

ü The last stack Element would point to NULL indicating the bottom of the stack.

Queue

ü Also contained a version of a linked list

ü Addition is done at the rear of the queue and deletion is done at the front of the queue.

ü FIFO data structure.

ü 2 pointers (one us to the front, one to the rear of the list.)

Basic Function

Init- sets the front and rear pointers to the NULL.

Enqueue – add a new data element to the rear of the Queue Element list by referencing the rear pointer to the new Element.

Dequeue- removesn the node in the queue list referenced by the front pointer by pointing it to the previous node.

IsEmpty –determines if the front pointer is NULL.

Trees

***Stacks and queue are linear data structure.

ü A binary tree is non-linear data structure with special properties.

ü A tree may contain 2 or more links.

ü Root node is first node of a tree.

Binary Trees

ü A binary tree has at most 2 links.

ü Each link in the root node refers to a child.

ü The left child is first node is the left subtree and the right child is the first node in right subtree.

ü The children of the node called sibilings.

ü Node of the sibilings-leaf node.

Files

ü Storage of the data in data structures and variables is a temp.

ü Used for permanent retention of large amount data.

ü Can access sequentially or randomly.

Data Hierarchy

ü Bit -Smallest data item is the binary digit .

ü Byte- A character is represented as a pattern of 8 bits. (8bits= 1 byte.)

ü Field- made up of a set of characters that conveys meaning.

ü Record – (structure in C) is normally made up of several related fields.

ü One field of a record is chosen as the key that is used to retrieval of a specific record.

Macro

ü Is a operation defined by the preprocessor.

ü May be defined with or without arguments

ü The macro-identifier is replaced in the program with the replacement text,

ü Can implemented (as C functions)

ü Symbolic constants. (#undef directive)

Pointers

ü Variables that contain memory addresses as their values.

ü Must be declared be4 used

ü May be initialised to NULL meaning that the pointer point to nothing.

Flow Chart

http://deming.eng.clemson.edu/pub/tutorials/qctools/flowm.htm - Overview<

Sys.Development Life Circle

http://searchvb.techtarget.com/sDefinition/0,,sid8_gci755068,00.html

Simplex of communication

http://www.pccompci.com/Transmission.html - Simplex

Network Architecture

http://networking.webopedia.com/TERM/c/client_server_architecture.html

Structured System Development

http://informaticshelp.hypermart.net/sa205/Ch2b.htm

^20 = 1,048,576 bytes = 1024 kilobytes. 1024 megabytes are one gigabyte.

A megabyte is a unit of measurement in computers of approximately one million bytes. The abbreviation for megabyte is MB.

Because of irregularities in definition and usage of the kilobyte, the exact number could be any one of the following:

1 000 000 bytes or 10⁶ - this is the definition used by telecommunications engineers and storage manufacturers among others. It is consistent with the SI prefix "mega".
1 048 576 bytes - 1024 times 1024, or 2²⁰. This definition is often used in computer science and computer programming.
1 024 000 bytes - 1024 times 1000. This is an (erroneous) definition used by floppy disk manufacturers

See integral data type.

A gigabyte is approximately 1000 or 1024 megabytes. Like the megabyte, its definition is variable.

A kilobyte is 1024 bytes.

A gigabyte is a unit of measurement in computers of approximately one thousand million bytes, (the same as one billion bytes in the American usage) or roughly 1000 megabytes.

Because of irregularities in definition and usage of the kilobyte, the exact number could be any of the following:

1 073 741 824 bytes - 1024 times 1024 times 1024, or 2³⁰. This is the definition used in computer science and computer programming.
1 000 000 000 bytes or 10⁹ - this is the definition used by telecommunications engineers and storage manufacturers.