Array elements in Java can have only one declared type (int[], char[], Person[], Animal[]) and it need not necessarily mean that it can hold elements only of that type.
Java Primitive array elements
If an array is declared as any Read more…
This is the third method for declaring, creating and initializing an array object in one line.
One Dimensional Array
or,
When you use this method size should not be specified.
Person[] arr = new Person[2] {p1, p2}; //ERROR
This method Read more…
This is the second method for declaring, creating and initializing an array object in one line.
Primitive
How this works?
- Declares a double array reference variable named studentAvgs;
- Creates a double array object in the memory with a length of
One Dimensional Array
Initializing an array means assigning values to the array elements. It can be either primitive values (12, 75.5, true, etc) or object reference (Animal, Person, String, etc)
null
Exception in thread “main” java.lang.NullPointerException
at com.ibytecode.arrays.TwoDReferenceArray.main(TwoDReferenceArray.java:17)
- Individual elements
All array objects have one built-in public variable to determine the length of an array.
Syntax:
arrayName.length
- This step creates an actual array object on the heap memory with the specified size i.e.) number of elements this array will hold.
- Size must be a positive integer value.
- This is done using new keyword/operator.
- This step is also
Syntax: One Dimensional Array
| Method 1 | Type[] arrayReferenceName; //Recommended |
|---|---|
| Method 2 | Type arrayReferenceName[]; //Legal, but not recommended |
Syntax: Two Dimensional Array
| Method 1 | Type[] [] arrayReferenceName; //Recommended |
|---|---|
| Method 2 | Type arrayReferenceName[] []; //Legal, but not recommended |
Type can be either Read more…
To create a database in MySQL, you use the CREATE DATABASE statement as follows:
CREATE {DATABASE | SCHEMA} [IF NOT EXISTS] db_name [create_specification] …
create_specification:
[DEFAULT] CHARACTER SET [=] charset_name
| [DEFAULT] COLLATE [=] collation_name
CREATE DATABASE statement will create Read more…
Why arrays?
Suppose we have a requirement to store average mark scored by each student. To accomplish this we define different variables (identifiers) of type double to store each student’s average mark.
 |
As you can see, it seems like a Read more…
1. Relational Database Management System (RDBMS)
- Software application that control the creation, maintenance, and use of a database.
- Based on the relational model.
- Data is stored in tables and the relationships among the data are also stored in tables.
- The