大家帮我看看这段程序

[XiaoG602]

为什么所求的体积(volume)是0啊~程序存在什么问题啊？
#include <iostream>
#include <cmath>
using namespace std;
const float pi=3.14;
class circle
{
protected:
float radii;
public:
circle(float r=1):radii(r){}
};

class line
{
protected:
float high;
public:
line(float h=0):high(h){}
void set_high();
};

void line::set_high()
{
cout<<"Please cin the high of the taper:";
cin>>high;
}

class taper:public circle,public line
{
public:
taper(float r=1,float h=0,float g=0):circle(r),line(h),generatrix(g){}
float taper_area();
float taper_volume();
void calculate_generatrix(){generatrix=sqrt(radii*radii+high*high);}
private:
float generatrix;
};

float taper::taper_area()
{
float area;
area=pi*radii*(generatrix+radii);
return area;
}

float taper::taper_volume()
{
float volume;
volume=(1/3)*pi*radii*radii*high;
return volume;
}

int main()
{
taper taper1;
taper1.set_high();
taper1.calculate_generatrix();
cout<<"The area is:"<<taper1.taper_area()<<endl;
cout<<"The volume is:"<<taper1.taper_volume()<<endl;
return 0;
}

[ttkk_2007]

void   line::set_high() 
{ 
cout < < "Please   cin   the   high   of   the   taper: "; 
cin> > high; 
} 
//输入的high根本就没有给line::high赋值

[babyvox1999]

float   taper::taper_volume() 
{ 
  float   volume; 
  volume=pi*radii*radii*high/3; 
  return   volume; 
} 

[babyvox1999]

原来1/3变成0了。。。。