Thread: Creating a random number

  1. #1
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    Creating a random number

    I need to create a random integer between 0 and 255, what function would I use and how would I accomplish this?

  2. #2
    Hurry Slowly vart's Avatar
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    rand()%256
    All problems in computer science can be solved by another level of indirection,
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    Also, how can I cast this number to a char?

  4. #4
    MFC killed my cat! manutd's Avatar
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    Code:
    char thechar[3];
    int num = rand()%256;
    itoa(num, thechar, 10);            //Note that this is not ANSI standard C.
    EDIT:Not a cast, but a function.
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  5. #5
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    Ah ok thanks.

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    My compiler didn't like itoa at all, are there any alternatives I can use?

  7. #7
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    I particularly don't see the problem with casting your number to a char, so long as it's between 0 and 255.
    Teacher: "You connect with Internet Explorer, but what is your browser? You know, Yahoo, Webcrawler...?" It's great to see the educational system moving in the right direction

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    Yes but how do I do it?

  9. #9
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    Code:
    int d = 65;
    char c = (char)d;
    Voila.

    In fact, I remember somewhere reading that you should keep chars in ints anyways...but I don't know if that's accurate at all.
    Teacher: "You connect with Internet Explorer, but what is your browser? You know, Yahoo, Webcrawler...?" It's great to see the educational system moving in the right direction

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    Ah cheers.

  11. #11
    MFC killed my cat! manutd's Avatar
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    Code:
    char thechar[3];
    int num = rand()%256;
    sprintf(thechar, "%d", num);
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  12. #12
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    I'm having a problem with the the random function. It's not very random.

    Everytime I run the program, it is picking the same numbers.

  13. #13
    MFC killed my cat! manutd's Avatar
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    Seed rand:
    Code:
    srand(time(NULL));
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  14. #14
    Hurry Slowly vart's Avatar
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    You should call it once - for example in the beginning of main
    All problems in computer science can be solved by another level of indirection,
    except for the problem of too many layers of indirection.
    David J. Wheeler

  15. #15
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    I get this message:

    warning: implicit declaration of function ‘time’

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