Implement pow(x, n).
将求幂转换为求对数的幂 . 如x^n = exp(n*log(x));
double pow(double x, int n) { //C++
if(x == 0.0)
return 0;
if(n == 0)
return 1.0;
bool isneg = false;
if(x < 0 ){
x = -x;
if(n%2 == 1)
isneg =true;
}
double result = exp(n*log(x));
if(isneg)
result = -result;
return result;
}原文:http://blog.csdn.net/chenlei0630/article/details/41787447