Computer Programming

• Object which contains elements of a similar data type


  Arrays
• Index-based, the first element of the array is stored at the 0th index, 2nd element is stored on 1st index and so on


  Arrays in Java
• Types of Arrays in Java


  Single Dimensional Array/One Dimensional Array, Two Dimensional and Multi Dimensional
• Considered as the "List if variables of similar data types"


  Single Dimensional Array or One Dimensional Array
• Single Dimensional or One Dimensional Array valid declarations


  int[] a; and int b[];
• int[] number = new int[5];


  Initialize an array named 'number' with the element of 5
• Array of arrays where data is organized into rows and columns (like an Excel file)


  Two Dimensional Array
• Two Dimensional Array valid declaration

  int a[][]; , int[][] b; and int[] c[];
• Multiple declaration of array variable


  int[] a[], b[]; , int[][] e, f[]; and int[] g[], h[];
• Ways to print an array in Java

  1. Java for loop
  2. Java for-each loop,
  3. Java Arrays.toString() method
  4. Java Arrays.deepToString() method
  5. Java Arrays.asList() method
  6. Java Iterator Interface
  7. Java Stream API
• Used to execute a set of statements repeatedly until a particular condition is satisfied 


  Java for Loop
• Java for Loop syntax

  for(initialization; condition; increment/decrement){

  //statement

  }
• Example of For Loop


  public class Main{

  public static void main(String[] args){

  int a[] = new int[4];

  a[0] = 10;
• Used to pass through an array or collection. Returns the elements one by one in a define variable 


  Java for-each loop
• Java for-each loop syntax


  for(Type var:array)
• Name assign to a storage area that the program can manipulate


  Variable
• A variable type determines the size and layout of the variable's memory
• Three places where variables you can declare variable programming language

  Inside a function or a block: Local Variable

  Outside of all function: Global Variables

  Definition of function parameters: Formal Parameters
• Local variable is declared inside a function whereas Global variable provides data sharing
• Created when the function has started execution and is lost when the function terminates


  Local Variables
• Variable that provides data sharing


  Global Variables
• Stored on the stack


  Local Variable
• Stored on a fixed location decided by the compiler


  Local Variables
• Parameters passing is required for local variable where as it is not necessary for the global variable
• Defined as a type of variable declared within programming block or subroutines


  Local Variable
• Local variable

  public int add(){

  int a = 4;

  int b = 5;

  return a+b;

  }
• Global Variable

  int a = 4;

  int b = 5;

  public int add(){

  return a+b;

  }