1.1 - Pointer, Array and Introduction to Data Structure - 2101702130 - Andrean

Pertemuan ke-1

20-02-2018

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 (0)

Array Declaration & Accessing Array

• One Dimensional Array

Syntax : type name[size];

Example :

Delcaration : 

int arr[5];

Accessing: 

• arr[0] = 2;
• arr[1] = 5;
• arr[2] = 1;
• arr[3] = 3;
• arr[4] = 4;

• Two Dimensional Array

Syntax : type name[size 1][size 2];

Example :

Delcaration : 

int arr[5][5];

Accessing:

• arr[0][2] = 1;
• arr[2][1] = 1;
• arr[1][2] = 2;
• arr[2][2] = 9;

• Multi Dimension Array

Syntax : type name[size 1][size 2][size 3][size...];

Example :

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;

note : there is no limit index of array at Multi Dimensional Array.

Operations in Array

• Traversal
• Insertion
• Searching
• Deletion
• Merging
• Sorting

Pointer

is a data type whose value refers to another value stored  

elsewhere in computer memory using its address.

two important operators used with pointer :

 & the address operator

 *  the dereferencing operator

Declration : 

• int x;
• int *px;

Example :

int a  = 10;
int *p = &a;

printf( " %d\n ", *p );

outcome : 10

Single Pointer vs Double Pointer

int a= 17; // let location be 1000

int *ptr,**ddptr; // creates two pointers let ptr have location 3000 and ddptr has location 4000.

ptr=&a; // ptr is initialized with address of a which is 1000

ddptr=&ptr; // ddptr  is initialized with address of address of ptr which is 3000. so ddptr contains 3000.

*ddptr; // gives output as value in the location pointed by ddptr. so it have value as 1000.b 

**ddptr ; will give 17, first it takes *ddptr it is 1000, then it takes *1000 that is 17.

this called double pointer.

source : https://www.quora.com/What-is-the-difference-between-the-single-pointer-and-double-pointer

note : you can use as many levels of pointers as you want.

Data Structure 

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

Example : 

• Arrays
• Linked lists
• Queues
• Stacks
• Binary trees
• Hash tables

Data Type

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

Example :

data type int consist :

• Object        : 1, 10, 100, etc
• Operations : +, -, /, etc

predefined data :

• int
• char
• float
• etc

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.

2101702130 - Andrean