arrays in java code example

Example 1: Arrays in java

// Accessing array elements using for loop
public class AccessingArrayElements
{
   public static void main(String[] args)
   {
      int[] arrNum = {25, 23, 15, 20, 24};
      for(int a = 0; a < arrNum.length; a++)
      {
         System.out.println(arrNum[a]);
      }
   }
}

Example 2: arrays in java

For example: int[ ] num = new int[6];
public class AccessingArrayElements
{
   public static void main(String[] args)
   {
      int[] arrNum = {25, 23, 15, 20, 24};
      for(int a = 0; a < arrNum.length; a++)
      {
         System.out.println(arrNum[a]);
      }
   }
}

Example 3: arrays in java

int[] intArray = new int[20];
String[] cars = {"Volvo", "BMW", "Ford", "Mazda"};

Example 4: arrays in java

int[] arr;			// Declaration dataType can int, float etc.
arr = new int[N];	// Allocation N = 0 to 2,147,483,647.

Example 5: arrays in java

3 data structures:
1. Array 2. Collection 3. Maps            
Arrays: a variable that can have multiple data    
DataType[]  variableName = { dat1, data2, data3 };
the data we are storing MUST match with DataTyp
each data in the array has its own index number

initializing the size of the array:
1. giving the values: size will be initialized automatically
	int[] arr = {10, 20, 30};
2. giving the size only: default value of the datatype will be assigned at each index
			                  int[] arr = new int[length];
			                  int[] arr = new int[5];
default values: byte, short, int, long ==> 0
			String or any object ==> null                        
length: returns the length of array
Array' size is fixed
Arrays utilities:
length: returns total number of the element of the arra
Arrays Utilities:
 Arrays class:  presented in "java.util"
             import java.util.Arrays;
 
Arrays.toString(arrayName): converts the array to String, returns the string
Arrays.sort(arrayName): sorts the given array in ascending order                    
Arrays.equals(arr1, arr2): chekcs if the two arrays are same or not. returns boolean 
 toCharArray(): returns char array from the string
String str = "Batch 18";
char[] ch   = str.toCharArray(); //['B', 'a', 't', 'c', 'h', ' ', '1', '8']

Array: size is fixed
       supports primitives and objects
       Can be multi-dimensional
       has index, accept duplicates
       Arrays.sort(arrayName);
       Collections.sort()

Example 6: arrays in java

int int_array[] = {10, 22, 475, 90, 54, 63}; // Brace-enclosed initializer list.

float float_array[]; // Array declaration/initialization with "new" keyword.
float_array = new float[SIZE_OF_ARRAY]; // Assume "SIZE_OF_ARRAY" is an integer.