02 January 2020

I have started reading the book From Mathematics to Generic Programming. In the second chapter the authors discuss an Egyptian method of multiplication that involves the use of a table. First you make the table and then you use it to perform multiplication. Below is a table for multiplying 21 by 23. Start with 1 x 23 and then double them for every following row. 1 + 1 is 2 and 23 + 23 is 46.

Multiple Result

1

23

2

46

4

92

8

184

16

368

This leverages the ease of adding something to itself to create the table. The algorithm uses addition to get the final result. We add 16 + 4 + 1 in the first column to get 21. Then we add the corresponding values in the second column to get the correct answer. 23 + 92 + 368 = 483.

Having read through the chapter I will now code my own implementation. Followed by an implementation of the authors version.


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