Array and 2 D Array in Java

 Array is an object in java, which contains similar type of data in a contiguous memory location. 

type[] arrayName = new type[size];
int[] marks = new int[10];

new keyword is used to allocate space in memory.

Simple Example 

class HelloWorld {
    public static void main(String[] args) {
        int myArray[] = {1,2,3,4,5};
        for(int i = 0; i<myArray.length; i++){
            System.out.println(myArray[i]);
        }
    }
}

1
2
3
4
5

import java.util.*;
class HelloWorld {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in); 
        System.out.print("Enter size: ");
        int n = sc.nextInt();
        int myArray[] = new int[n];
        
        for(int i= 0; i<n; i++){
            System.out.print("Enter value: ");
            myArray[i] = sc.nextInt();
        }
        System.out.print("Output: ");
        for(int j = 0; j<n; j++){
            System.out.println(myArray[j]);
        }
    }
}

Enter size: 5
Enter value: 1
Enter value: 2
Enter value: 3
Enter value: 4
Enter value: 5
Output: 1
2
3
4
5

Take an array as input from the user. Search for a given number x and print the index at which it occurs.

import java.util.Scanner;
public class MyClass {
    public static void main(String args[]) {
      System.out.print("Enter Size: ");
      Scanner sc = new Scanner(System.in);
      int n = sc.nextInt();
      
      int myArray[] = new int[n];
      
      System.out.print("Enter Array value: ");
      for(int i = 0; i<n; i++){
          myArray[i] = sc.nextInt();
      }
      
      System.out.print("Show Values : ");
      for(int j = 0; j<myArray.length; j++){
          System.out.println(myArray[j]);
      }
      
      System.out.print("Enter Value for search: ");
      int search = sc.nextInt();
      for(int k = 0; k<myArray.length; k++){
          if(myArray[k] == search){
              System.out.println("Value found in:" +k+" position");
          }
      }
    }
}

Enter Size: 5
Enter Array value: 1
2
3
4
5
Show Values : 1
2
3
4
5
Enter Value for search: 4
Value found in:3 position