Fibonacci Sequence - Ruby One-Liners

[animanmaster]

Please describe your program and how to run it.

This PR adds two Ruby scripts to print out the n-th number of the Fibonacci Sequence. (Related to Issue #210 for #hacktoberfest)

fibonacci.rb implements this recursively, clearly following the mathematical definition of the Fibonacci sequence. However, as you all know, this naive implementation can be highly inefficient, and should not be executed for large n values unless you enjoy hearing your computer's fan whir. :)

fibonacci_iterative.rb implements this iteratively, keeping track of the last two Fibonacci numbers each iteration until we reach the final result.

Both programs can be run while passing an n value into the script, like so:

λ ruby fibonacci.rb 10
55

λ ruby fibonacci_iterative.rb 10
55

But as mentioned above, fibonacci_iterative is the more efficient version. For comparison, take a look at the runtime of both versions when n = 30:

$ time ruby fibonacci.rb 30
832040

real    0m0.554s
user    0m0.266s
sys     0m0.109s

$ time ruby fibonacci_iterative.rb 30
832040

real    0m0.088s
user    0m0.063s
sys     0m0.016s

λ powershell -Command "Measure-Command {ruby fibonacci.rb 30}"


Days              : 0
Hours             : 0
Minutes           : 0
Seconds           : 0
Milliseconds      : 375
Ticks             : 3753132
TotalDays         : 4.34390277777778E-06
TotalHours        : 0.000104253666666667
TotalMinutes      : 0.00625522
TotalSeconds      : 0.3753132
TotalMilliseconds : 375.3132

λ powershell -Command "Measure-Command {ruby fibonacci_iterative.rb 30}"


Days              : 0
Hours             : 0
Minutes           : 0
Seconds           : 0
Milliseconds      : 133
Ticks             : 1336232
TotalDays         : 1.54656481481481E-06
TotalHours        : 3.71175555555556E-05
TotalMinutes      : 0.00222705333333333
TotalSeconds      : 0.1336232
TotalMilliseconds : 133.6232

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What Programming Language?

Ruby

[wzhouwzhou]

Thank you for making the first Ruby program in this repository, as well as for comprehensive testing!