In this part of my blog, I will try to give some information about java primitive data types, their range and default value of the types.
The Java programming language is statically-typed, which means that all variables must first be declared before they can be used. Before using any variable in your program, you must declare the variable with its type and name.
For example:
int data = 1;
This declaration tells your program that there is a field named “data”, holds numerical data, and has an initial value of "1".
Primitive data types and their range:
boolean :1 bit
range - May take on the values “true” and “false” only.
byte :1 byte
range - form -128 to 127
short :2 bytes
range – from -32,768 to 32,767
int :4 bytes
range – from -2,147,483,648 to 2,147,483,647
long :8 bytes
range – from -9,223,372,036,854,775,808
to 9,223,372,036,854,775,807
float :4 bytes
range – from 1.40129846432481707e-48
to 3.40282346638528860e+38
(positive or negative)
double :8 bytes
range – from 4.94065645841246544e-324d
to 1.79769313486231570e+308d
(positive or negative)
char :2 bytes, unsigned, unicode
range – from 0 to 65,535
String :a sequence of characters
We must know the range of the types to use them effectively in our programs. For example we have a counter, it starts with the value of 0 and it increases continuously. Initially for this counter as primitive type “int” will be sufficient. But in the future, the value of the counter will increase and it will be outside the range of int. so the program will not work correctly.
As developer if you do not assign a value to a variable you declare, it will be assigned will its default value.
Default values for the data types:
Data Type Default Value
byte :0
short :0
int :0
long :0L
float :0.0f
double :0.0d
char :’\u0000’
boolean :false
String :null
I wish to be useful.
