Arrary

Arrays

• Set of finite homogeneous elements
  (collection of fixed same elements)
• contain one type of data (all. integer, all character)
• consecutive memory location

Array Format

• Elements : integers, floats, characters
• all elements share a common name with an index called subscript

Arrarys in c

• Declaration: int arr[10];
• int: data type
• arr : name
• [10] : size or length
  array_type array_name[size];
• Read/write through loops

Advvantages of Arrary

• represents multiple data
• implement other data structure(stacks, queues,tree)
• two-dimensional arrays
• databases-one dimensional arrays

Disadvantages of Array

• must know in advance the number elements
• static structure(fixed size, constant allocated memory)
• consecutive memory location

Represent a Linear Array

size of an Array

total bytes=sizeof(data type)*size of array

Initializing arrays

• array elements must be initialized at time of declaration(if not, contained garbage valeus)
• initialization can be done either at compile time or run time

Compile Time Initialization

• int num[3]={1,1,1};
• float fl_num[5]={1.0,12.50,100.35}
  : initialized first three elements
  : Rest two will be initialized to 0.
• exceeds size of array=> compiler error

int num=[]={5,10,-20,0,1000};
array size will automatically be set equal to the number of initial values

Basic operations of Arrays

• Traversing, Insertion, Deletion, Searching, Sorting, Merging

Traversing Arrays

Insertion into Arrary

 

Deletion from Arrary

 

Searching in Arrarys

Linear/Sequential Search

Binary Search

sort->divide one two smaller sub-arrays->recursively operate->reduceds the search space to half

Linear&Binary

Sorting

• arrangement of the elements
  : Numeric array -ascending, descending
• bubble, selection, shell, quick, heap, insertion

Merging

 

Types of Arrarys

• Single Dimension array (one subscript)
• Two Dimension Array (two subscript: Rows and Column)
• Multi Dimension Array (Multiple subscripts)

Two dimensional array

• num[m][n]
  :m=row, n=column

 

Row-major method

• all the first-row elements are stored in sequential memory location
• second-row elements are stored and so on A[Row][Col]

Column-major Method

• all the first column elements are stored in sequential memory locations
• all the second-coulmn elements are stored and so on A[Col][Row]

store table, matrix

Multidimensional Arrays

-first dimension is called a plane-consists of rows and columns

• three-dimensional array =>array of two-dimensional array