Factorial or Product, need explanations


#1

Hi,

Can someone please explain me the meaning of the following code:

  • I don't get why one should set the variable fact to 1 on line 2
  • I don't understand the logic behind fact *= i and i+= 1 on line 4 and 5

I guess it has something to do with my lack of skills in math... :sweat:

`


#2

*= and += are compound operators for multiplication assignment and addition assignment.

fact = 1

is initialized to unity since it has no effect on multiplying. It gives us a starting factor to multiply the rest against.

f *= n

When f is 1, the assignment after multiplying will make f equal to n. As the loop progresses, the new value for n will continue to increase the value of f.


#3

That I understand... but why doing this ?


#4

Compound operators are step saving devices.

i += 1

# is the same as,

i = i + 1


f *= n

# is the same as,

f = f * n

#5

Thank you very much for your quick and comprehensive answer, I think i get it now !
You guys are the best.


#6

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