problem with recursive power function

[chofs]

hey guys am having a problem with my power function that calculates power it works properly with exponents that are intergers but crashes with exponents that are double type please help thanx in advance

 double power(double base, double exp)
{


    if ( exp == 0 )
        return 1;
    else if ( exp == 1 )
        return base;
    else
        return base * power(base, exp-1);
    double result = base;

}

[MiiNiPaa]

if ( exp == 0 ) Do not compare floating point values which you get as a computation result for equality directly.

What happens if I pass 0.5 as exponent?

Using recursion to calculate power of arbitrary values is not good. You shpould use more elaborate math in here.

[chofs]

can u help me impliment such a condition in my function am out of ideas.....

[MiiNiPaa]

From math we know that pow(x, n) = exp(n * log(x))
Now you need to implement exp and log functions. There is many ways to do that (either by using naive approach with Tailor series or doing something smarter), but I will suggest to jusr use tandard functions. If you still want to make your own functions, there is reference log() implementation: http://www.netlib.org/fdlibm/e_log.c


Actually for perfomance math functions are often implemented directly in assembly.