#include<iostream>
#include<cmath>
using namespace std;
int main()
{
double m;
for(int i=1;i<=64;i++)
{
int a;
a=i-1;
m=m+pow(2,a);
}
cout<<m<<endl;
return 0;
}
标签：std,main,return,int,18,include From： https://www.cnblogs.com/guozi6/p/17392036.html