# Implementing the LengthProxy Object

Learn how to implement the LengthProxy object for comparing and calculating lengths while preventing misuse.

`LengthProxy`

object

Itâ€™s time to implement the `LengthProxy`

class containing a `float`

data member that represents the squared length. The actual squared length is never exposed to prevent users of the class from mixing the squared length with the regular length.

Instead, `LengthProxy`

has a hidden `friend`

function that compares its squared length with a regular length, as follows:

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