generating random numbers using srand

This is a discussion on generating random numbers using srand within the C Programming forums, part of the General Programming Boards category; hi i want to generate numbers from 65 to 90 using srand and i dont want a number to be ...

  1. #1
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    generating random numbers using srand

    hi i want to generate numbers from 65 to 90 using srand and i dont want a number to be generated twice and put them in an array how can i do that

  2. #2
    ATH0 quzah's Avatar
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    Read the FAQ. Use an array. Check for duplicates. Use some loops.


    Quzah.
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    and the hat of wrongness Salem's Avatar
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    Read the FAQ
    There's an answer in there.
    http://faq.cprogramming.com/
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
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    well i couldnt find i can generate numbers from 1 to 6 but when i try to generate 65 to 90 it generates 150 140 ... im a beginner

  5. #5
    and the hat of wrongness Salem's Avatar
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    http://faq.cprogramming.com/cgi-bin/...&id=1043284385
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    Read about GetRand

    > using srand
    srand() seeds the pseudo random sequence, use rand() to deliver each successive number in the pseudo random sequence.

    > i dont want a number to be generated twice
    Mmm, 65 to 90 - you mean 'A' to 'Z' ?
    char buff[26];
    for ( i = 0, c = 'A' ; i < 26 ; i++, c++ ) buff[ i ] = c;

    Or even
    char buff[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    That's the uniqueness bit sorted out.

    Now shuffle them to produce a random order.
    Do a board search, shuffling arrays was discussed quite recently
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  6. #6
    MFC killed my cat! manutd's Avatar
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    You don't generate the numbers using srand. srand seeds rand, giving the rand algorithm a starting value. rand() does the work. Check out this link.
    EDIT: Beaten.
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