There are two types of variables. Primative data types and classes/objects. Primative datatypes are treated slightly differently to classes. In order to treat them more like classes you have to use a wrapper class but we will come onto that later!
The primative data types you can use are -
Type |
Java shorthand |
Range |
Size |
Example |
| Integer | int | -2,147,483,648 to 2,147,483,647 | 4 | 8 |
| Long integer | long | -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 | 8 | 8,033,321,23 |
| float | float | 1.40129846 x 10 ^ -45 to 3.40282366 x 10 ^ 38 |
8 | 6.4 |
| double | double | 4.94065 x 10 ^ -324 to 1.79769 x 10 ^ 308 |
16 | 93.98321 |
| boolean | boolean | true / false | 1 |
false |
| character | char | single letter | 1 | g |
When you create a variable you must decide on what type of data it will store up front. This choice is very important as if you try and store a number that is too big or compare different types together you will get errors.
Remember Java can not compare different data types!