Java with BlueJ, 2016a

28 CHAPTER 2. BASICS
The output from the above is:
Default Decimal Data Type
When a numeric literal (such as 100.25) appears in a program and has a
decimal point, the data type used is double; wesaythatdouble is the default
data type for values with a decimal point. If the programmer wanted
to use a float value then the suffix f would be used, as in 100.25f.
To a non-programmer literals such as 100.0 and 100 may seem the same,
but a Java programmer knows the first is represented internally as a double
and the second is represented as an int.
We say that double and int are the default numeric data types. We focus
on these numeric data types for the rest of this text.
Exercises
8. Modify the program in Listing 2.4 to calculate and display fuel consumption
as the number of kilometres travelled per litre of fuel.
9. Write a program that converts a value in centimetres to an equivalent
value in inches. Use the conversion: one inch equals 2.54 centimetres.
Use variables of type double.
10. Write a program that converts a value in dollars to an equivalent value
in euros. Use the conversion: one euro equals 1.5 dollars. Use variables
of type double.
11. Modify Listing 2.5 to run some different calculations, such as:
System.out.println(100.5-100.00);
System.out.println(100.33-100.00);