建立类cylinder,cylinder的构造函数被传递了两个double值，分别表示圆柱体的半径和高度。用类cylinder计算圆柱体的体积，并存储在一个double变量中。在类cylinder中包

#include<iostream>

#include<cstring>

using namespace std;

class Cylinder {

double r;

double h;

double vol;

    public:

void r_h_input()

{ 

 cout<<"please input r,h:";

 cin>>r>>h;

}

void v_volume_out()

{vol=3.14*r*r*h;

printf("The volume of cylinder is:%f\n",vol);

}

 

};

int main()

{ Cylinder v1;

  v1.r_h_input();

   v1.v_volume_out();

  return 0;

}