HSC: Two classes; Cone, Cube

#include<iostream.h>
#include<conio.h>

class cone
{
float r,h,l;
public:
float area(float r,float l);
float vol(float r,float h);
};

class cube
{
float l;
public:
float area(float l);
float vol(float l);
};

float cone::area(float r,float l)
{
    float acone = 3.14*r*l;
    cout<<acone<<endl;
    return acone;
}
float cone::vol(float r,float h)
{
    float vcone=0.333*r*r*h*3.14;
    cout<<vcone<<endl;
    return vcone;
}

float cube::area(float l)
{
    float acube=6*l*l;
    cout<<acube<<endl;
    return acube;
}

float cube::vol(float l)
{
    float vcube=l*l*l;
    cout<<vcube<<endl;
    return vcube;
}

void add(float x, float y)
{
    float z = x+y;
    cout<<"The sum is"<<z<<endl;
}


void main()
{
float r,lco,lcu,h,ra1,rv1,ra2,rv2;
clrscr();
cone co;
cube cu;
cout<<"Enter r,l,h of cone"<<endl;
cin>>r>>lco>>h;
cout<<"Enter l for cube:"<<endl;
cin>>lcu;
ra1=co.area(r,lco);
rv1=co.vol(r,h);
ra2=cu.area(lcu);
rv2=cu.vol(lcu);
add(ra1,ra2);
add(rv1,rv2);
getch();
}