Unlike primitive data types, any array has to be created using the
new operator. A reference to an array can be declared without any elements and can be assigned to null. A reference can be further modified as well.
To create an array, you first must create an array variable of the desired type. The general form of a one-dimensional array declaration is
type var-name = new type[desired-length];
- type tells the element type e.g.,
- var-name gives the variable name e.g.,
- new allocates memory required for the array with the size mentioned at desired-length e.g., 5, 12
The following code creates an array of student marks for a class with 25 students. And all elements in the array are initialized to zero automatically.
int student_marks = new int;
- Arrays are allocated at run-time, hence we can use a variable to set their dimension.
int array_size = 100;
float my_array = new float[array_size]; // array_size should be of type byte, short or int
- You can assign an array a null value but you can't create an empty array by using a blank index.
int array = null; // legal
int array = new int; // illegal initialization
- The length of the array can be obtained using the
length variable in array. This variable will be useful when iterating through the values of an array.
Accessing array elements
int array = new int;
System.out.println("Array length is " + array.length);
explains about how to access the array elements i.e.
how to assign values to elements of an array and how to read them.