Is the following an integer literal? 197.0
No — it has a decimal point.
If you use the literal 197.0 in a program, the decimal point tells the compiler to represent the value using a floating point primitive data type. The bit pattern used for floating point 197.0 is very much different than that used for the integer 197. There are two floating point primitive types.
float is sometimes called "single-precision floating point".
double has twice as many bits and is sometimes called
"double-precision floating point".
These phrases come from the language FORTRAN,
at one time the dominant programming language.
In source programs, floating point literals always have a decimal point in them, and no commas (no thousand's separators):
123.0 -123.5 -198234.234 0.00000381
Note: Literals written like the above will automatically be
Almost always, if you are dealing with floating point numbers you
should use variables of type
Then the data type of literals like the above will match the data type
of your variables.
float should be used only for special circumstances
(such as when you need to process a file of data containing 32 bit floats).
|Floating Point Primitive Data Types|
|float||32 bits||-3.4E+38 to +3.4E+38|
|double||64 bits||-1.7E+308 to 1.7E+308|
(Thought question: ) Do you think that using
double saves a significant amount of computer