c语言 求一个数的n次方

#include <stdio.h>

double pow (double num, int n)
{
    int c;
    double d=1;
    for(c=0;c<n;c++)
    {
        d = d * num;
    }
    return d;
}

int main()
{
    double num;
    int n;
    scanf ("%lf%d",&num,&n);
    printf("%lf\n",pow(num,n));
    return 0;
}