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28 lines
510 B
Ruby
28 lines
510 B
Ruby
=begin
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A ruby program calculate factorial of a given number.
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Mathematical Explanation: The factorial of a number is the product of all the integers from 1 to that number.
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i.e: n! = n*(n-1)*(n-2)......*2*1
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=end
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def factorial(n)
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if n < 0
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return nil
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end
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fac = 1
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while n > 0
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fac = fac * n
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n -= 1
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end
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return fac
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end
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puts '4! = ' + factorial(4).to_s
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# 4! = 24
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puts '0! = ' + factorial(0).to_s
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# 0! = 1
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puts '10! = ' + factorial(10).to_s
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# 10! = 3628800
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