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Constants

Variables are a powerful tool, but sometimes you want to use a defined value, one whose value you want to ensure remains constant. A constant is like a variable in that it can store a value. However, unlike a variable, you cannot change the value of a constant while the program runs.

For example, you might need to work with the Fahrenheit freezing and boiling points of water in a program simulating a chemistry experiment. Your program will be clearer if you name the variables that store these values `FreezingPoint` and `BoilingPoint`, but you do not want to permit their values to be changed while the program is executing. The solution is to use a constant. Constants come in three flavors: literals, symbolic constants, and enumerations.

Literal Constants

A literal constant is just a value. For example, 32 is a literal constant. It does not have a name; it is just a literal value. And you can’t make the value 32 represent any other value. The value of 32 is always 32. You can’t assign a new value to 32, and you can’t make 32 represent the value 99 no matter how hard you might try. You’ll use literal constants a lot, but you probably won’t think of them as such.

Symbolic Constants

Symbolic constants assign a name to a constant value. You declare a symbolic constant using the following syntax:

`const `type identifier` =`value;``

The `const` keyword is followed by a type, an identifier, the assignment operator (`=`), and the value to assign to the constant.

This is similar to declaring a variable ...

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