java for array code example

Example 1: how to declare array java

int intArray[];    //declaring array
intArray = new int[20];  // allocating memory to array
//OR
int[] intArray = new int[20]; // combining both statements in one

Example 2: how to declare an array in java

An array is an ordered collection of elements of the same type, identified by a pair of square brackets []. 
 
 To use an array, you need to:
1. Declare the array with a name and a type. Use a plural name for array, e.g., marks, rows, numbers. All elements of the array belong to the same type.
2. Allocate the array using new operator, or through initialization, e.g.
  
  int[] marks;  // Declare an int array named marks
              // marks contains a special value called null.
int marks[];  // Same as above, but the above syntax recommended
marks = new int[5];   // Allocate 5 elements via the "new" operator
// Declare and allocate a 20-element array in one statement via "new" operator
int[] factors = new int[20];
// Declare, allocate a 6-element array thru initialization
int[] numbers = {11, 22, 33, 44, 55, 66}; // size of array deduced from the number of items

Example 3: array in java

//method 1
int[] age = new int[3];
        age[0] = 1;
        age[1] = 3;
        age[2] = 6;

        for (int i=0; i < 3; i++)
            System.out.println(age[i]);

//method 2
        int[] num = {3,3,5};
        //int num[] = {3,3,5}; also works the same

        System.out.println(num[0]);

Example 4: string array in java methods

String[] vowels = { "a", "e", "i", "o", "u" };
System.out.println(vowels);
System.out.println(Arrays.toString(vowels));

Example 5: arrays in java

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

Example 6: how to use for loop for array in java

// Java program to iterate over an array 
// using for loop 
import java.io.*; 
class GFG { 
  
    public static void main(String args[]) throws IOException 
    { 
        int ar[] = { 1, 2, 3, 4, 5, 6, 7, 8 }; 
        int i, x; 
  
        // iterating over an array 
        for (i = 0; i < ar.length; i++) { 
  
            // accessing each element of array 
            x = ar[i]; 
            System.out.print(x + " "); 
        } 
    } 
}