char type in java

Character data type:

• Character type can store characters, symbols and digits.
• Character represents using ‘single quotes’.

class CharacterType 
{
	public static void main(String[] args) 
	{
		char x = 'a';
		char y = '5';
		char z = '#';
		System.out.println("x : " + x + "\ny : " + y + "\nz : " + z);
	}
}

Character System:

• Program is a set of instructions.
• Instruction consists alphabets, digits and symbols.
• System converts every instruction into binary format.
• It uses character system to convert all symbols in the program into binary values.
• Character system represents all symbols of a language using constant integer values.
• Examples ASCII and UNICODE.

ASCII: Americans Standard Code for Information Interchange

• C, C++ languages follow ASCII character system.
• ASCII set represents all symbols using 0-255 integer values.
• 1 byte memory can able to store a value between 0-255, hence character size is 1 byte in C and C++ languages.

We can store integer values into character type:

class DataTypes 
{
	public static void main(String[] args) 
	{
		char x = 65;
		char y = 57;
		char z = 35;
		System.out.println("x val : " + x);
		System.out.println("y val : " + y);
		System.out.println("z val : " + z);
	}
}

Output:
x val : A
y val : 9
z val : #

We can display the integer values of symbols by storing directly into int type variables:

class DataTypes 
{
	public static void main(String[] args) 
	{
		int x = 'a';
		int y = '5';
		int z = '$';
		System.out.println("x val : " + x);
		System.out.println("y val : " + y);
		System.out.println("z val : " + z);
	}
}

Output:
x val : 97
y val : 53
z val : 36

Program to display the Complete ASCII character set

class ASCII 
{
	public static void main(String[] args) 
	{
		System.out.println("ASCII Character Set : ");
		for (int i=0 ; i<256 ; i++)
		{
			System.out.println(i + " : " + (char)i);
		}
	}
}

Why character size is 1 byte in C and C++?

• C and C++ languages are platform dependent.
• Using C and C++, we can develop only Standalone applications.
• Standalone application represents only one language character set at a time.
• Using 1 byte range(256), we can represent the symbols of 1 language.

UNICODE: Universal Code

• The size of UNICODE character is 2 bytes.
• The programming languages (java, .net, python…) are using UNICODE character system in web applications development.
• Web applications need to represent more than one language character set at a time.
• To represent more than 1 language character set; 1 byte memory is not enough, hence it occupies 2 bytes.
• For example a web application can run from multiple machines with different languages at a time.

• A web application needs to specify more than 1 language character set.
• Hence each character occupies 2 bytes memory – UNICODE
• UNICODE – 2 bytes
  • 65536
  • 256 x 256
  • 256 languages
• A Unicode character system can represent up to 256 languages at a time.