replacing a loop with recursion

This is a discussion on replacing a loop with recursion within the C Programming forums, part of the General Programming Boards category; I'm trying to replace my a loop in a exponent function but I'm not sure how to go about doing ...

  1. #1
    Advanced Novice linucksrox's Avatar
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    replacing a loop with recursion

    I'm trying to replace my a loop in a exponent function but I'm not sure how to go about doing it... thanks for any help
    Code:
    double power(double a, double b)
    {
        double pow = 1;
        int i = 1;
        char flag = OFF;            /* the reason for using (char) is that it only takes up 1 byte */
    
        if (b == 0)
          return a;
    
        if (b < 0)
          flag = ON;
    
        if (i <= b)                      /* this loop is what's messed up... */
          pow *= power(a, i + 1);
    
        if (flag == ON)
          pow = 1 / power(a, -b);
    
        return pow;
    }
    that loop would normally be
    Code:
    for (i = 1; i <= b; i++)
      pow *= a;
    but that's my poor attempt at recursion...
    Last edited by linucksrox; 04-14-2004 at 06:11 PM.

  2. #2
    ggs
    ggs is offline
    C > C++ duders ggs's Avatar
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    try power(a, b-1);

    i dun think you need i anymore
    .sect signature

  3. #3
    Advanced Novice linucksrox's Avatar
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    thanks, I finally got it. I still don't quite understand it, but it works fine.
    Code:
    double power(double a, double b)
    {
        double pow = a;
        char flag = OFF;            /* the reason for using (char) is that it only takes up 1 byte */
    
        if (b < 0)
          flag = ON;
    
        if (b > 0)
          pow *= power(a, b - 1);
    
        if (flag == ON)
          pow = 1 / power(a, -b);
    
        if (b == 0)
          pow = 1;
    
        return pow;
    }

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