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  4. How do I generate a number divisable by 5, and check it?

How do I generate a number divisable by 5, and check it?

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  • S stephen darling

    Hi. First, how would I create a random number, and then add the last digit, so that it is divisable by 5? the number should always be 5 digits long. Second, how do I check it, I think I need to do something like...

    if (int x MOD 5 ==0)

    Or something like that. The first step is the most important though. Thank you, Steve

    L Offline
    L Offline
    Lost User
    wrote on last edited by
    #18

    Didn't you already post this in the Q&A and get an answer to it?? Generating numbers to the multiple of 5?[^]

    Computers have been intelligent for a long time now. It just so happens that the program writers are about as effective as a room full of monkeys trying to crank out a copy of Hamlet.

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    • D David1987

      Nope. You seem to think that that is the only definition of divisibility. I did not personally redefine anything. There is no natural number n such that 0/x=n so no x evenly divides 0. If you use the definition with integers instead of natural numbers, everything divides zero. Also, the prime factorization of zero is empty.

      L Offline
      L Offline
      Luc Pattyn
      wrote on last edited by
      #19

      natural numbers are the ordinary counting numbers 1, 2, 3, ... (sometimes zero is also included) is what Wikipedia[^] offers as a definition. Now you can choose: either you include zero and you are allowed to use it at both sides of your 0/x=n, or you exclude it (and then your "except zero" remark that started all this is completely irrelevant). :doh:

      Luc Pattyn [My Articles] Nil Volentibus Arduum

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      • OriginalGriffO OriginalGriff

        Luc Pattyn wrote:

        Next you'll state you could also redefine 5, so it no longer divides itself.

        It doesn't. There are only four bacon sandwiches left... :laugh:

        Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together. Manfred R. Bihy: "Looks as if OP is learning resistant."

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        L Offline
        Luc Pattyn
        wrote on last edited by
        #20

        Sorry for the late reply, I have been off-line this evening, I have another tournament going on this week. I trust all bacon sandwiches have magically disappeared by now, and so the problem got solved? :)

        Luc Pattyn [My Articles] Nil Volentibus Arduum

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        • S stephen darling

          riced wrote:

          If a number is divisible by 5 it must end in 5 or 0

          Yes; I was getting confused with the coding issue not the actual math.

          riced wrote:

          that's primary school arithmetic.

          I know, I am a Biomedical Scientist.

          riced wrote:

          If you don't believe me write out the 5 times table for the numbers 1 to 20.

          I do believe you. Like I said, it was the coding side of things. However, it is my fault the way I explained myself, it did indeed look as though I didn’t understand the math itself, and I certainly was not questioning you answer. Sorry if it came across that way, and thank you. Kind Regards, Stephen

          M Offline
          M Offline
          Mycroft Holmes
          wrote on last edited by
          #21

          Your confusion did lead me to think - how old is this guy, doesn't understand primary grade maths :-D

          Never underestimate the power of human stupidity RAH

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          • L Luc Pattyn

            natural numbers are the ordinary counting numbers 1, 2, 3, ... (sometimes zero is also included) is what Wikipedia[^] offers as a definition. Now you can choose: either you include zero and you are allowed to use it at both sides of your 0/x=n, or you exclude it (and then your "except zero" remark that started all this is completely irrelevant). :doh:

            Luc Pattyn [My Articles] Nil Volentibus Arduum

            D Offline
            D Offline
            David1987
            wrote on last edited by
            #22

            Yes but that's precisely the point, you can choose.

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            • D David1987

              Generate a random integer in [2000, 19999] and multiply it by 5. The result will always be in [10000, 99999] (ie 5 decimal digits) and be divisible by 5 (by construction)

              int yourNumber = 5 * rand.Next(2000, 20000); // remember the max-bound is exclusive
              if (yourNumber % 5 != 0)
              Console.WriteLine("the universe is wrong");

              And make sure you reuse a single instance of Random, if you create new ones the result won't be random. [/spoon feeding]

              S Offline
              S Offline
              stephen darling
              wrote on last edited by
              #23

              David1987 wrote:

              And make sure you reuse a single instance of Random,

              How exactly do I ensure that I am doing this? I am using rand a number of times, and although I get different values, it does appear that they are very simular. Regards, Stephen

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              • D David1987

                Nope. You seem to think that that is the only definition of divisibility. I did not personally redefine anything. There is no natural number n such that 0/x=n so no x evenly divides 0. If you use the definition with integers instead of natural numbers, everything divides zero. Also, the prime factorization of zero is empty.

                B Offline
                B Offline
                BobJanova
                wrote on last edited by
                #24

                That is a stupid definition. It would also indicate that -10 is not divisible by 5. There may be abstruse mathematical concepts for which it's useful, I suppose, but for normal maths it is nonsense.

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                • S stephen darling

                  Does this mean that no matter what number I generate, it will always have to end in 5? e.g. All these numbers are divisable by 5

                  39485
                  99045
                  12095
                  49385
                  99335

                  However, I was under the impression I could generate numbers that would be divisable by 5, but not end in 5? Is this wrong? Regards, Stephen

                  G Offline
                  G Offline
                  Gary Wheeler
                  wrote on last edited by
                  #25

                  All integers evenly divisible by 5 must end in either 5 or 0 when expressed in base 10. This is basic math.

                  Software Zen: delete this;

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                  • S stephen darling

                    Hi. First, how would I create a random number, and then add the last digit, so that it is divisable by 5? the number should always be 5 digits long. Second, how do I check it, I think I need to do something like...

                    if (int x MOD 5 ==0)

                    Or something like that. The first step is the most important though. Thank you, Steve

                    T Offline
                    T Offline
                    Tom Chantler
                    wrote on last edited by
                    #26

                    Is this a joke question? Generate a four digit number and add an extra number to the end, being either 5 or 0. Then don't check it because it will be correct!!! e.g. 4678; add 5 on the end to give 46785.

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                    • S stephen darling

                      Hi. First, how would I create a random number, and then add the last digit, so that it is divisable by 5? the number should always be 5 digits long. Second, how do I check it, I think I need to do something like...

                      if (int x MOD 5 ==0)

                      Or something like that. The first step is the most important though. Thank you, Steve

                      P Offline
                      P Offline
                      Paulo_JCG
                      wrote on last edited by
                      #27

                      Random random = new Random(); return (random.Next(17999) + 2000) * 5; this gives a number divisable by 5 between 10000 and 99995

                      Paulo Gomes Over and Out :D

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                      • S stephen darling

                        riced wrote:

                        If a number is divisible by 5 it must end in 5 or 0

                        Yes; I was getting confused with the coding issue not the actual math.

                        riced wrote:

                        that's primary school arithmetic.

                        I know, I am a Biomedical Scientist.

                        riced wrote:

                        If you don't believe me write out the 5 times table for the numbers 1 to 20.

                        I do believe you. Like I said, it was the coding side of things. However, it is my fault the way I explained myself, it did indeed look as though I didn’t understand the math itself, and I certainly was not questioning you answer. Sorry if it came across that way, and thank you. Kind Regards, Stephen

                        M Offline
                        M Offline
                        mmwlada
                        wrote on last edited by
                        #28

                        stephen.darling wrote:

                        riced wrote:

                        that's primary school arithmetic.

                        I know, I am a Biomedical Scientist.

                        You are NOT a scientist. A scinetist knows elementary math. You should be ashamed of yourself.

                        There can be only one.

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                        • M mmwlada

                          stephen.darling wrote:

                          riced wrote:

                          that's primary school arithmetic.

                          I know, I am a Biomedical Scientist.

                          You are NOT a scientist. A scinetist knows elementary math. You should be ashamed of yourself.

                          There can be only one.

                          S Offline
                          S Offline
                          stephen darling
                          wrote on last edited by
                          #29

                          mmwlada wrote:

                          You are NOT a scientist. A scinetist knows elementary math. You should be ashamed of yourself.

                          How dare you! I may be a beginner in the programming world, but to be spoken to in this way from someone who does not know me is extremely rude! I am indeed a scientist, registered in the UK as a practising biomedical scientist, not that I need to explain myself to you! As for the math, if you took the time to read through the post, you would see that I simply explained myself wrong, and it was the programming that I was struggling with, and not the math. As for being ashamed of myself; I do not know what your problem is, but believe me, I have nothing to be ashamed of, and could now go on to say allot about, and to you, however, I will refrain! Stephen

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                          • S stephen darling

                            riced wrote:

                            If a number is divisible by 5 it must end in 5 or 0

                            Yes; I was getting confused with the coding issue not the actual math.

                            riced wrote:

                            that's primary school arithmetic.

                            I know, I am a Biomedical Scientist.

                            riced wrote:

                            If you don't believe me write out the 5 times table for the numbers 1 to 20.

                            I do believe you. Like I said, it was the coding side of things. However, it is my fault the way I explained myself, it did indeed look as though I didn’t understand the math itself, and I certainly was not questioning you answer. Sorry if it came across that way, and thank you. Kind Regards, Stephen

                            F Offline
                            F Offline
                            FunkySteve
                            wrote on last edited by
                            #30

                            Actually, every number is divisible by 5.

                            S 1 Reply Last reply
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                            • F FunkySteve

                              Actually, every number is divisible by 5.

                              S Offline
                              S Offline
                              stephen darling
                              wrote on last edited by
                              #31

                              FunkySteve wrote:

                              Actually, every number is divisible by 5

                              True. Again, my fault for not explaining properly. I meant a modulus of zero, so that 13285 MOD 5 = 0 Got it all sorted now, thanx to most people, disregarding one perticular ignorant comment :confused: Thank you, Steve

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                              • L Luc Pattyn

                                a random multiple of five is bound to be five times some other random number. :omg:

                                Luc Pattyn [My Articles] Nil Volentibus Arduum

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                                F Offline
                                Fabio Franco
                                wrote on last edited by
                                #32

                                I'd say you're stating the obvious, but then, I remember when I was very young and inexperienced and I couldn't see stuff like this. So, it's not always obvious as one might think. You got my five.

                                "To alcohol! The cause of, and solution to, all of life's problems" - Homer Simpson

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                                • S stephen darling

                                  Does this mean that no matter what number I generate, it will always have to end in 5? e.g. All these numbers are divisable by 5

                                  39485
                                  99045
                                  12095
                                  49385
                                  99335

                                  However, I was under the impression I could generate numbers that would be divisable by 5, but not end in 5? Is this wrong? Regards, Stephen

                                  K Offline
                                  K Offline
                                  Kenneth Kasajian
                                  wrote on last edited by
                                  #33

                                  Is this discussion really taking place? What is this, 3rd grade?

                                  ken@kasajian.com / www.kasajian.com

                                  S 1 Reply Last reply
                                  0
                                  • F Fabio Franco

                                    I'd say you're stating the obvious, but then, I remember when I was very young and inexperienced and I couldn't see stuff like this. So, it's not always obvious as one might think. You got my five.

                                    "To alcohol! The cause of, and solution to, all of life's problems" - Homer Simpson

                                    L Offline
                                    L Offline
                                    Luc Pattyn
                                    wrote on last edited by
                                    #34

                                    I tend to state facts, even obvious ones, especially when it seems to OP is missing them somehow. Rather than spoon feeding, I prefer to give a gentle push in the right direction... :)

                                    Luc Pattyn [My Articles] Nil Volentibus Arduum

                                    F 1 Reply Last reply
                                    0
                                    • K Kenneth Kasajian

                                      Is this discussion really taking place? What is this, 3rd grade?

                                      ken@kasajian.com / www.kasajian.com

                                      S Offline
                                      S Offline
                                      stephen darling
                                      wrote on last edited by
                                      #35

                                      Kenneth Kasajian wrote:

                                      Is this discussion really taking place? What is this, 3rd grade?

                                      What is everones problem? I asked how to solve a basic math based problem PROGMATICALLY as I am a beginner when it comes to c#, and I am wishing I never bothered asking! Although, there are a number of people who have offered working solutions. Why must people post such a responce as yours? Did your post really help in anyway? Regards, Stephen

                                      K 1 Reply Last reply
                                      0
                                      • L Luc Pattyn

                                        I tend to state facts, even obvious ones, especially when it seems to OP is missing them somehow. Rather than spoon feeding, I prefer to give a gentle push in the right direction... :)

                                        Luc Pattyn [My Articles] Nil Volentibus Arduum

                                        F Offline
                                        F Offline
                                        Fabio Franco
                                        wrote on last edited by
                                        #36

                                        Completely agree, I'm totally against the "gimme codezzzz plz" culture.

                                        "To alcohol! The cause of, and solution to, all of life's problems" - Homer Simpson

                                        1 Reply Last reply
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                                        • D David1987

                                          Nope. You seem to think that that is the only definition of divisibility. I did not personally redefine anything. There is no natural number n such that 0/x=n so no x evenly divides 0. If you use the definition with integers instead of natural numbers, everything divides zero. Also, the prime factorization of zero is empty.

                                          A Offline
                                          A Offline
                                          ARon_
                                          wrote on last edited by
                                          #37

                                          http://mathworld.wolfram.com/EvenNumber.html[^] Note zero is an even number and by definition dividable by two, the answer is just zero. As a recall from calculus I, you can't divide a number by zero but you can divide a number as the devisor approaches zero.

                                          ARon

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