Constant Declarations
The use of symbolic constants is very important for making programs easily and correctly modifiable.
| Scheme: | (define pi 3.14) |
| Pascal: | const pi = 3.14; |
| C++: | #define PI 3.14 |
| Java: | static final double = 3.14; |
In Pascal, const declarations must appear before var declarations in the program.
Note that #define in C++ specifies text replacement, so it should not have a ; at the end.
In many languages, there must be a digit on both sides of the decimal point in a floating-point constant: 3.0 or 0.1 .