Loop Replacement

Loop Replacement
A Programming Pattern

Prof. David Bernstein
James Madison University

Computer Science Department

bernstdh@jmu.edu

Motivation

A Common Feature of Programs:
- Nested Loops
A Common Shortcoming:
- The code can be very difficult to read and understand when the bodies of the loops are complicated

A Solution

Loop Replacement:
- Replace (one or more of) the inner loop(s) with a method call (often a private method)
An Observation:
- This is really just a particular kind of functional decomposition

An Example - A Moving Average

The Description:
- Each element in a moving average of a data array is the mean of the corresponding element in the data array and a fixed number of previous elements
The Math (0-Based Indexing):
- \(m_i = \left( \sum_{i-n+1}^{i} d_i \right) / n, \text{ for } i = n-1, N-1\)
A Visualization:

Moving Average (cont.)

A "Naive" Implementation

javaexamples/programmingpatterns/LoopReplacement.java

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