New program need help with factorials

This is a discussion on New program need help with factorials within the C++ Programming forums, part of the General Programming Boards category; I need to know how to find the factorial (5!=125) of a variable and, using it and for loops, put ...

  1. #1
    hacker in training AdamLAN's Avatar
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    New program need help with factorials

    I need to know how to find the factorial (5!=125) of a variable and, using it and for loops, put all of the possible combinations in an array.

  2. #2
    Registered User hk_mp5kpdw's Avatar
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    Quote Originally Posted by AdamLAN
    I need to know how to find the factorial (5!=125) of a variable
    Use a loop to calculate the factorial.

    Quote Originally Posted by AdamLAN
    and, using it and for loops, put all of the possible combinations in an array.
    Huh? Combinations of what into the array?
    "Owners of dogs will have noticed that, if you provide them with food and water and shelter and affection, they will think you are god. Whereas owners of cats are compelled to realize that, if you provide them with food and water and shelter and affection, they draw the conclusion that they are gods."
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    #include<xErath.h> xErath's Avatar
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    factorial of x is x*factorial(x-1), and factorial 0 is 1
    have fun... I'd sugest a cicle instead of recursion... recursion does functions call, which have a big overhead and use lots of stack.

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    Quote Originally Posted by AdamLAN
    5!=125
    Close... 5! = 120.

  5. #5
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    AdamLAN,

    Do you know what a factorial is? Can you do it by hand or on a calculator? ... I mean a calculator without a factorial button.

    5! means 1 x 2 x 3 x 4 x 5 = 120. (Of course, that's NOT C++ because x does NOT mean multiply in C++.)

    Step 1
    If you can't figure-out the whole program, how about starting with a loop that generates the sequential integers 1 thru n: 1, 2, 3, 4...

    Step 2
    When that's working, add the code to calculate the factorials.

    Step 3
    When you get that working, add the array stuff.

    I assume that by "all the possible combinations" you mean this all of the factorials up to n: 1, 2, 6, 24...
    Last edited by DougDbug; 05-20-2005 at 01:31 PM.

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