递归大总结之指数运算

来自剑指offer

#include<iostream>
using namespace std;
double power(int b, int e)
{
if (e < 0)
{
e = -e;
}
if (e == 0)
{
return 1;
}
if (e == 1)
{
return b;
}
double res = power(b, e >>1);
res *= res;
if (e & 0x1)
{
res = res*b;
}

return res;
}
int main()
{
int a, b;
cin >> a >> b;
double res=power(a,b);
if (b < 0)
{
res = 1 / res;
}
cout << res << endl;
system("pause");
}