Has preloaded and allowed customizable schemes for calculating a tip. The user can define a scheme, which is a list of categories; a category is a list of criteria; a criteria is a list of weighted names. Then the tip is calculated as the some of these weights. Some example categories could be food taste, service speed, server politeness, etc. So, the patron doesn't tip based on numbers; he/she tips bases on pre-defined weights assigned to attributes of the service.

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