Data Types and Casting
Every variable must have a data type. A variable's data type determines the values that the variable can contain and the operations that can be performed on it.
The Java programming language has two categories of data types: primitive and reference.
Primitive Data Types (ones we will use in the course)
Data Type |
Minimum Value |
Maximum Value |
short |
-32768 |
32767 |
int |
-2147483648 |
2147483647 |
long |
-9223372036854775808 |
-9223372036854775807 |
float |
-3.4e+38 |
3.4e+38 |
double |
-1.8e+308 |
1.8e+308 |
char |
Objects, instantiations of classes, are reference data types.
Casting
This is a technique to change the data type of a primitive variable for the current operation only.
Example 1:
double height = 60.45;
System.out.println((int) height); would be used to print the integer portion of the height
Example 2:
int a = 10;
int b = 3;
System.out.println (a/b): will print 3
System.out.println ((double)a/b) will print 3.3333
Example 3: