java aray code example

Example 1: 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 2: 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 3: array java

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

Example 4: java array

// ! IMPORTANTE !
// in JAVA an array is not the same as an ArrayList object!!
// 1 - declare, instanciate and populate
int arr[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }; 
// 2 - declare and instanciate an int array with maxSize
// note: the index goes between 0 and maxSize-1
int newarr[] = new int[maxSize];
// 2.1 - insert the value n on the position pos
newarr[pos] = n; 
// 2.2 - insert values recursively
for (i = 0; i < maxSize; i++) { newarr[i] = arr[i]; }