A constant is a value that cannot be altered by the program during normal execution, i.e., the value is constant. When associated with an identifier, a constant is said to be "named," although the terms "constant" and "named constant" are often used interchangeably. This is contrasted with a variable, which is an identifier with a value that can be changed during normal execution, i.e., the value is variable.
In some languages, or under some circumstances, only the memory address is constant, but not its contents, i.e. the variable can not be re-assigned, but the value can be mutated.
- What values can be made constant?: are there restrictions to what values can be made constant?
- How to make a value a constant?: what is the syntax to make a value constant?
- How to use constants?: how can one refer to a constant?
This exercise deals with cooking a lasagna dish in the oven. The reference implementation (Ruby) teaches:
- How to define a constant
- How to refer to a constant.
| Track | Exercise | Changes |
|---|---|---|
| JavaScript | basics | None |
| Ruby | basics | None |