Here below a little program in Cobra that implements 2 classes (in fact, they are 3). There is the main class, called Fiborial (Fibo(nnacci)+(Facto)rial) that implements the Fibonacci and the Factorial algorithms in two ways, one Recursive (using recursion) and the other Imperative (using loops and states). The second class is just an instance class that does the same thing, but its there just to show the difference between static and instance classes, and finally the third one (which will not appear in other languages) is the Program class which has the static execution method "Main".
You can also find 3 more little examples at the bottom. One prints out the Factorial's Series and Fibonacci's Series, the second one just shows a class that mixes both: static and instance members, and finally the third one that uses different return types (including System.Numerics.BigInteger) for the Factorial method to compare the timing and result.
As with the previous posts, you can copy and paste the code below in your favorite IDE/Editor and start playing and learning with it. This little "working" program will teach you some more basics of the Programming Language.
There are some "comments" on the code added just to tell you what are or how are some features called. In case you want to review the theory, you can read my previous post, where I give a definition of each of the concepts mentioned on the code. You can find it here: http://carlosqt.blogspot.com/2011/01/new-series-factorial-and-fibonacci.html
The Fiborial Program
# Factorial and Fibonacci in Cobra
use System.Collections.Generic
use System.Diagnostics
use System.Numerics
namespace FiborialCobra
# Static Class
class StaticFiborial is public
shared
# Static Field
var __className as String
# Static Constructor
cue init
__className = 'Static Constructor'
print '[__className]'
# Static Method - Factorial Recursive
def factorialR(n as int) as BigInteger is public
if n == 1
return BigInteger.one
else
return BigInteger.multiply(BigInteger(n), .factorialR(n - 1))
# Static Method - Factorial Imperative
def factorialI(n as int) as BigInteger is public
res as BigInteger = BigInteger.one
for i as int in n:0:-1
res = BigInteger.multiply(res, BigInteger(i))
return res
# Static Method - Fibonacci Recursive
def fibonacciR(n as int) as int64 is public
if n < 2
return 1
else
return .fibonacciR(n - 1) + .fibonacciR(n - 2)
# Static Method - Fibonacci Imperative
def fibonacciI(n as int) as int64 is public
pre as int64 = 1
cur as int64 = 1
tmp as int64 = 0
for i as int in 2:n+1
tmp = cur + pre
pre = cur
cur = tmp
i=i # ignore compiler warning
return cur
# Static Method - Benchmarking Algorithms
def benchmarkAlgorithm(algorithm as int, values as List<of int>) is public
timer as Stopwatch = Stopwatch()
i as int = 0
testValue as int = 0
facTimeResult as BigInteger = BigInteger.zero
fibTimeResult as int64 = 0
facTimeResult = facTimeResult
fibTimeResult = fibTimeResult
# "if-elif-else" Flow Control Statement
if algorithm == 1
print '\nFactorial Imperative:'
# "For in range" Loop Statement
for i as int in values.count
testValue = values[i]
# Taking Time
timer.start
facTimeResult = .factorialI(testValue)
timer.stop
# Getting Time
print ' ([testValue]) = [timer.elapsed]'
else if algorithm == 2
print '\nFactorial Recursive:'
# "While" Loop Statement
while i < values.count
testValue = values[i]
# Taking Time
timer.start
facTimeResult = .factorialR(testValue)
timer.stop
# Getting Time
print ' ([testValue]) = [timer.elapsed]'
i += 1
else if algorithm == 3
print "\nFibonacci Imperative:"
# "Do-While" Loop Statement
post while i < values.count
testValue = values[i]
# Taking Time
timer.start
fibTimeResult = .fibonacciI(testValue)
timer.stop
# Getting Time
print ' ([testValue]) = [timer.elapsed]'
i += 1
else if algorithm == 4
print "\nFibonacci Recursive:"
# "For in List" Loop Statement
for i as int in values.count
testValue = values[i]
# Taking Time
timer.start
fibTimeResult = .fibonacciR(testValue)
timer.stop
# Getting Time
print ' ([testValue]) = [timer.elapsed]'
else
print 'DONG!'
# Instance Class
class InstanceFiborial is public
# Instances Field
var __className as String
# Instance Constructor
cue init
base.init
__className = "Instance Constructor"
print __className
# Instance Method - Factorial Recursive
def factorialR(n as int) as BigInteger is public
# Calling Static Method
return StaticFiborial.factorialR(n)
# Instance Method - Factorial Imperative
def factorialI(n as int) as BigInteger is public
# Calling Static Method
return StaticFiborial.factorialI(n)
# Instance Method - Fibonacci Recursive
def fibonacciR(n as int) as int64 is public
# Calling Static Method
return StaticFiborial.fibonacciR(n)
# Instance Method - Fibonacci Imperative
def fibonacciI(n as int) as int64 is public
# Calling Static Method
return StaticFiborial.fibonacciI(n)
# Console Program
class Program is public
def main is shared
print '\nStatic Class'
# Calling Static Class and Methods
# No instantiation needed. Calling method directly from the class
print 'FacImp(5) = [StaticFiborial.factorialI(5)]'
print 'FacRec(5) = [StaticFiborial.factorialR(5)]'
print 'FibImp(11)= [StaticFiborial.fibonacciI(11)]'
print 'FibRec(11)= [StaticFiborial.fibonacciR(11)]'
print '\nInstance Class'
# Calling Instance Class and Methods
# Need to instantiate before using. Call method from instantiated obj
ff as InstanceFiborial = InstanceFiborial()
print 'FacImp(5) = [ff.factorialI(5)]'
print 'FacRec(5) = [ff.factorialR(5)]'
print 'FibImp(11)= [ff.fibonacciI(11)]'
print 'FibRec(11)= [ff.fibonacciR(11)]'
# Create a List of integer values to test
# From 5 to 50 by 5
values as List<of int> = List<of int>()
for i as int in 5:55:5
values.add(i)
# Benchmarking Fibonacci
# 1 = Factorial Imperative
StaticFiborial.benchmarkAlgorithm(1, values)
# 2 = Factorial Recursive
StaticFiborial.benchmarkAlgorithm(2, values)
# Benchmarking Factorial
# 3 = Fibonacci Imperative
StaticFiborial.benchmarkAlgorithm(3, values)
# 4 = Fibonacci Recursive
StaticFiborial.benchmarkAlgorithm(4, values)
# Stop and Exit
Console.read
And the Output is:
Humm, looks like Fibonnaci's algorithm implemented using recursion is definitively more complex than the others 3 right? I will grab these results for this and each of the upcoming posts to prepare a comparison of time execution between all the programming languages, then we will be able to talk about the algorithm's complexity as well.
Printing the Factorial and Fibonacci Series
use System.Text
use System.Numerics
namespace FiborialSeries
# Instance Class
class Fiborial is public
shared
# Using a StringBuilder as a list of string elements
def getFactorialSeries(n as int) as String is public
# Create the String that will hold the list
series as StringBuilder = StringBuilder()
# We begin by concatenating the number you want to calculate
# in the following format: '!# ='
series.append('!')
series.append(n)
series.append(' = ')
# We iterate backwards through the elements of the series
for i as int in n:0:-1
# and append it to the list
series.append(i)
if i > 1
series.append(' * ')
else
series.append(' = ')
# Get the result from the Factorial Method
# and append it to the end of the list
series.append(.factorial(n))
# return the list as a string
return series.toString
# Using a StringBuilder as a list of string elements
def getFibonnaciSeries(n as int) as String is public
# Create the String that will hold the list
series as StringBuilder = StringBuilder()
# We begin by concatenating the first 3 values which
# are always constant
series.append('0, 1, 1')
# Then we calculate the Fibonacci of each element
# and add append it to the list
for i as int in 2:n+1
if i < n
series.append(', ')
else
series.append(' = ')
series.append(.fibonacci(i))
# return the list as a string
return series.toString
def factorial(n as int) as BigInteger is public
if n == 1
return BigInteger.one
else
return BigInteger.multiply(BigInteger(n), .factorial(n - 1))
def fibonacci(n as int) as int64 is public
if n < 2
return 1
else
return .fibonacci(n - 1) + .fibonacci(n - 2)
# Console Program
class Program is public
def main is shared
# Printing Factorial Series
print ''
print Fiborial.getFactorialSeries(5)
print Fiborial.getFactorialSeries(7)
print Fiborial.getFactorialSeries(9)
print Fiborial.getFactorialSeries(11)
print Fiborial.getFactorialSeries(40)
# Printing Fibonacci Series
print ''
print Fiborial.getFibonnaciSeries(5)
print Fiborial.getFibonnaciSeries(7)
print Fiborial.getFibonnaciSeries(9)
print Fiborial.getFibonnaciSeries(11)
print Fiborial.getFibonnaciSeries(40)
Console.read
And the Output is:
Mixing Instance and Static Members in the same Class
Instance classes can contain both, instance and static members such as: fields, properties, constructors, methods, etc.
namespace FiborialExtrasCobra2
# Instance Classes can have both: static and instance members.
# Instance Class
class Fiborial is public
# Instance Field
var __instanceCount as int
# Static Field
var __staticCount as int is shared
# Instance Read-Only Property
pro instanceCount as int is public
get
return __instanceCount
# Static Read-Only Property
# Remeber that Properties are Methods to the CLR, so,
# you can also define static properties for static fields.
pro staticCount as int is shared, public
get
return __staticCount
# Instance Constructor
cue init
base.init
__instanceCount = 0
print '\nInstance Constructor [__instanceCount]'
# Static Constructor
cue init is shared
__staticCount = 0
print '\nStatic Constructor [__staticCount]'
# Instance Method
def factorial(n as int) is public
__instanceCount += 1
print '\nFactorial([n])'
# Static Method
def fibonacci(n as int) is shared, public
__staticCount += 1
print '\nFibonacci([n])'
# Console Program
class Program is public
def main is shared
# Calling Static Constructor and Methods
# No need to instantiate
Fiborial.fibonacci(5)
# Calling Instance Constructor and Methods
# Instance required
fib as Fiborial = Fiborial()
fib.factorial(5)
Fiborial.fibonacci(15)
fib.factorial(5)
# Calling Instance Constructor and Methods
# for a second object
fib2 as Fiborial = Fiborial()
fib2.factorial(5)
print ''
# Calling Static Property
print 'Static Count = [Fiborial.staticCount]'
# Calling Instance Property of object 1 and 2
print 'Instance 1 Count = [fib.instanceCount]'
print 'Instance 2 Count = [fib2.instanceCount]'
Console.read
And the Output is:
Factorial using System.Int64, System.Double/Float, System.Numerics.BigInteger
The Factorial of numbers over 20 are massive!
For instance: !40 = 815915283247897734345611269596115894272000000000!
Because of this, the previous version of this program was giving the "wrong" result
!40 = -70609262346240000 when using "long" (System.Int64) type, but it was not until I did the Fiborial version in VB.NET that I realized about this faulty code, because instead of giving me a wrong value, VB.NET, JScript.NET, Boo execution thrown an Overflow Exception when using the "Long/long" (System.Int64) type.
My first idea was to use ulong and ULong, but both failed for "big" numbers. I then used Double (double floating point) type and got no more exception/wrong result. The result of the factorial was now correct !40 = 1.1962222086548E+56, but still I wanted to show the Integer value of it, so I did some research and found that there is a new System.Numerics.BigInteger class in the .NET Framework 4.0. Adding the reference to the project and using this new class as the return type of the Factorial methods, I was able to get the result I was expecting.
!40 = 815915283247897734345611269596115894272000000000
What I also found was that using different types change the time the algorithm takes to finish:
System.Int64 < System.Double < System.Numerics.BigInteger
Almost by double!
To illustrate what I just "tried" to say, lets have a look at the following code and the output we get.
use System.Diagnostics
use System.Numerics
namespace FiborialExtrasCobra3
class FiborialExtrasProgram
shared
def main
timer as Stopwatch = Stopwatch()
facIntResult as int64 = 0
facDblResult as float = 0
facBigResult as BigInteger = BigInteger.zero
i as int = 0
print '\nFactorial using Int64'
# Benchmark Factorial using Int64
for i as int in 5:55:5
timer.start
facIntResult = .factorialInt64(i)
timer.stop
print ' ([i]) = [timer.elapsed] : [facIntResult]'
print '\nFactorial using Float'
# Benchmark Factorial using float
for i as int in 5:55:5
timer.start
facDblResult = .factorialFloat(i)
timer.stop
print ' ([i]) = [timer.elapsed] : [facDblResult]'
print '\nFactorial using BigInteger'
# Benchmark Factorial using BigInteger
for i as int in 5:55:5
timer.start
facBigResult = .factorialBigInteger(i)
timer.stop
print ' ([i]) = [timer.elapsed] : [facBigResult]'
Console.read
# Long Factorial
def factorialInt64(n as int) as int64
if n == 1
return 1
else
return n * .factorialInt64(n - 1)
# float/Number Factorial
def factorialFloat(n as int) as float
if n == 1
return 1
else
return n * .factorialFloat(n - 1)
# BigInteger Factorial
def factorialBigInteger(n as int) as BigInteger
if n == 1
return BigInteger.one
else
return BigInteger.multiply(BigInteger(n), .factorialBigInteger(n - 1))
NOTE: you need to manually add a reference to the System.Numerics.dll assembly to your project so you can add it to your code.
And the Output is:
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