Pert ke 1 - Pointer, Array and Introduction to Data Structure - 2101680123 - Milliady Kusnadi The Bu Hiap

Pointer, Array and
Introduction to Data Structure

A.   Array

•         A collection of similar data elements

•         These data elements have the same data type (homogenous)

•         The elements of the array are stored in consecutive memory locations and are referenced by an index

•         Array index starts from zero

*Array Declaration & Accessing Array

Declaration:

•      int arr[5];

Accessing:

•      arr[0] = 7;

•      arr[1] = 2;

•      arr[2] = 13;

•      arr[3] = 13;

•      arr[4] = 13;

*Array Declaration & Accessing Array

Two Dimensional Array

Declaration:

•      int arr[3][6];

Accessing:

•      arr[0][2] = 2;

•      arr[2][1] = 9;

•      arr[1][5] = 13;

•      arr[2][4] = 10;

Syntax:

          type name[size1][size2];

•      The first index of array ranged from 0 to size1 – 1.

•      The second index of array ranged from 0 to size2 – 1.

*Array Declaration & Accessing Array

Multi Dimensional Array

Declaration:

•      int arr[4][3][7][10];

Accessing:

•      arr[0][2][2][9]= 2;

•      arr[2][1][6][0]= 9;

•      arr[3][0][0][6]= 13;

•      arr[2][1][3][8]= 10;

Syntax:

type ame[size1][size2][size3][...];

•      The first index of array ranged

from 0 to size1 – 1.

•      The second index of array ranged

from 0 to size2 – 1.

•      The third index of array ranged

from 0 to size3 – 1.

•      and so on.

*Storing Array Values

•         Initialization of Arrays

          Example:    int marks[5] = {90, 82, 78, 95, 88};

•         Inputting Values

          Example:    int i, marks[10];

                             for (i=0; i<10; i++)

                                      scanf(“%d”, &marks[i]);

•         Assigning Values

          Example:    int i, arr1[10], arr2[10];

                             for(i=0; i<10; i++)

                                      arr2[i] = arr1[i];

*Operations in Array

There are a number of operations that can be performed

on arrays. They are:

•         Traversal

•         Insertion

•         Searching

•         Deletion

•         Merging

•         Sorting

B.   Pointer

Pointer is a data type whose value refers to another value stored 

elsewhere in computer memory using its address.

The two most important operators used with pointer type are:

 & the address operator

 * the dereferencing operator

If we have the declaration:

     int x;

     int *px;

then x is an integer and px is a pointer to an integer. If we say:

     px  = &x;

then &x returns the address of x and assigns it as the value of px.

To assign a value of x we can say

     x = 10;

     *pi = 10;

What is the output of this program?

int a  = 10;

int *p = &a;

printf( “%d\n”, *p );

a  = 17;

*p = 20;

printf( “%d\n”, a );

C.   Data Structure

•      A data structure is an arrangement of data, either in the computer’s memory or on the disk storage.

•      Some common examples of data structures include:

–     Arrays

–     Linked lists

–     Queues

–     Stacks

–     Binary trees

–     Hash tables

*Types of Data Structure

•      Arrays

–     A collection of similar data elements

–     Data elements have the same data type

·           Linked Lists

–     A very dynamic data structure in which the elements can be added to or deleted from anywhere at will

–     Each element is called a node

·           Queue

–     The element that was inserted first is the first one to be taken out

–     The elements in a queue are added at one end called the rear and removed from the other end called the front

·           Stacks

–     Stacks can be represented as a linear array

–     Every stack has a variable TOP associated with it

–     LIFO (Last In First Out) / FILO (First In Last Out)

–     Binary Trees

–     A data structure which is defined as a collection of elements called the nodes

–     Every node contains a left pointer, a right pointer, and a data element

D.   Data Type

•      Data Type is a collection of objects and a set of operations that act on those objects.

•      For example, the data type int consists of:

•         objects                  : 0, +1, -1, +2, -2, etc

•         operations  : +, -, *, /, %, etc

•      Example of predefined data types are int, char, float.

*Abstract Data Type

•      Abstract Data Type (ADT) is a data type that is organized in such a way that the specification of the objects and the specification of the operations on the objects is separated from the representation of the objects and the implementation of the operations.

•      C/C++ has a concept called class and struct which assist the programmer in implementing abstract data type.

*Example of ADT

•      Supposed we want to create an ADT of natural number which has integer number as objects and several functions as operation.

•      structure Number is

          objects        : an integer x

          functions     :

                   bool is_zero()       if ( x == 0 ) return TRUE else return FALSE

                   bool equal(y)        if ( x == y ) return TRUE else return FALSE

                   void set(y)  x = y

                   void add(y) x = x + y

                   int get ()                return x

E.   Summary

•      Pointer is a data type whose value refers to another value stored elsewhere in computer memory using its address

•      Array is a collection of similar data elements

•      Array index starts from zero

•      A data structure is an arrangement of data, either in the computer’s memory or on the disk storage

•      Some common examples of data structures include: arrays, linked lists, queues, stacks, binary trees, hash tables

•      Abstract Data Type (ADT) is a data type that is organized in such a way that the specification of the objects and the specification of the operations on the objects is separated from the representation of the objects and the implementation of the operations