Making A Random Number Each Time?

This is a discussion on Making A Random Number Each Time? within the C++ Programming forums, part of the General Programming Boards category; Ok so I want it so whenever I put in the command roll_dice it will print out 5 random numbers. ...

  1. #1
    Me
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    Making A Random Number Each Time?

    Ok so I want it so whenever I put in the command roll_dice it will print out 5 random numbers. I figured I was going to run across this problem. But whenever I use the function "roll_dice" it just print's out the same number's each time, like if I print them out twice during the program. Here is the function.

    Code:
    int roll_dice()
    {
    int dice[5];
    srand(time(NULL));
    
    dice[1]=rand()%6+1;
     dice[2]=rand()%6+1;
     dice[3]=rand()%6+1;
     dice[4]=rand()%6+1;
     dice[5]=rand()%6+1;
    
    cout<<dice[1];
     cout<<dice[2];
     cout<<dice[3];
     cout<<dice[4];
     cout<<dice[5];
    }
    It should print out 5 random number's each time I use the function, but it print's out the same ones.

  2. #2
    pwns nooblars
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  3. #3
    Code Goddess Prelude's Avatar
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    >It should print out 5 random number's each time I use the function, but it print's out the same ones.
    That's because you reseed the generator each time you call the function. srand should be called sparingly, usually only once in a short running program.

    >http://members.cox.net/srice1/random/crandom.html
    Hmm, I'm not sure I'd recommend that link...
    My best code is written with the delete key.

  4. #4
    pwns nooblars
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    I thought it was the link I have at my home computer that teaches better practices for getting more random numbers.... Sorry bout that. Do what Prelude said.

  5. #5
    (?<!re)tired Mario F.'s Avatar
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    I recommend Prelude's link: http://eternallyconfuzzled.com/articles/rand.html

    Read the whole thing even though your problem is related with the seeding method.

    Also, roll_dice() seems to not return anything. You may want to declare it void, instead of int.
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    Reimplementing a large system in another language to get a 25% performance boost is nonsense. It would be cheaper to just get a computer which is 25% faster.

  6. #6
    Me
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    Yes, I just figured that out after posting...I hate when that happens, but yes it work's fine now thanks. I'll read the article as well.

  7. #7
    Rabite SirCrono6's Avatar
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    If you haven't already noticed, you're also trying to access elements 1-5, instead of 0-4.
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