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6.1: The Advantage - Encapsulation and Re-Use

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    As you know, a mathematical function is a "rule" which given some inputs (or arguments), returns an output or outputs. A MATLAB function (or a function in any programming language), is very similar: the function, given some inputs/arguments, returns an output or outputs. There are two main reasons that functions are so important and useful as a programming construct: re-use and encapsulation. First, re-use: if we perform a particular set of operations - for example, calculation of \(\sin (x)\) for given \(x\) - we prefer not to re-write this same code over and over again. Rather, we write it once and then use it over and over again, with enormous savings. Second, encapsulation: a user can take advantage of the function, and the "function" it performs - from inputs to outputs without knowing how this function has been implemented or what is "inside" the code; from another perspective, what happens inside the function does not affect the user’s higher level objectives the output is the entire "effect" (we discuss this further below).

    We have already taken extensive advantage of both re-use and encapsulation: we have used many MATLAB built-in functions in all of our examples above; and we have used these functions not only without knowing "what is inside" but in fact without even knowing how a function is defined syntactically. In actual practice, it would not be good to proceed in quite such a trusting fashion.

    This page titled 6.1: The Advantage - Encapsulation and Re-Use is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Masayuki Yano, James Douglass Penn, George Konidaris, & Anthony T Patera (MIT OpenCourseWare) via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.