Expressions

   

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In any action or method that requires parameters, you can place a variable or an expression instead of a fixed value. That said, variables can store any type of data. You can use them to hold Boolean values such as true and false statements, and you can use them to assign other variables a value.

Expressions are formulas that combine variables with other variables or values. Therefore, an expression may contain variables, properties, and objects that need to be solved or figured out to determine its value. An expression's value must be calculated before it is assigned to the variable name .

Another way to use variables is as tracking devices. Instead of taking the place of a specific parameter, a tracking variable keeps track of the number of times certain occurrences happen. This information is stored and can be used later. For example, the correct answers to a test can be stored and used to compare against the end user 's answers to determine how many people answered correctly.

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