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Question: What is datatype?


Question: What is datatype?

AnswerDatatype 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



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


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-

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

OUTPUT –







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


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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