Question: What is datatype?

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Question: What is datatype?

Answer – Datatype is a set of values that has an associated set of operations and a memory representation for its values.

S. NO.	DATA TYPE	SIGN IN BYTES	DEFAULT VALUES
1.	char	2	\0 (Null Character)
2.	byte	1	0
3.	short	2	0
4.	int	4	0
5.	long	8	0
6.	float	4	0
7.	double	8	0
8.	boolean	Not defined	false

2. class Test1
3. {
4. public static void main(String args[])
5. {
6. int a;
7. System.out.println("a = “ + a); // Compilation error
8. }
9. }

Output -

Explanation-

v  Concept of default value is not applied on local variables of method i.e. local variables of a method need to be explicitly assigned.

v  Default value will be applied in class variables.

Like for example the above program can be rewritten as-

2. PROGRAM Test1.java
3. class Test1
4. {
5. static int a, b;
6. public static void main(String args[])
7. {
8. System.out.println("a & b is : " + a + " " + b); // No compilation error
9. }
10. }

OUTPUT –

2. PROGRAM Test2.java
3. class Test2
4. {
5. public static void main(String args[])
6. {
7. float f = 12.45;
8. System.out.println("Value of f = " + f);
9. }
10. }

What will be the output –

A.     Value of f = 12.45

B.     Value of f = 12

C.     Value of f = 12.00000

D.     Compilation Error  (output)

Now let’s see the output of the above program.

Explanation –

In Java, floating point constants are of double type by default. The value of higher type cannot be directly assigned to a lower type. In such a case type conversion is required.

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