Thread: Inheritance:

I am getting runtime errors that say:

Code:

Linker (id) Error
"circle::circle()" reference from:

Linker (id) Error
"cylinder::cylinder()",reference from:

Code:

#include <iostream>

using namespace std;

class circle {
    
protected:
    double radius=1.0;

public:
    circle();
    
    const double PI = 3.14;
    
    void setRadius(double a){
        radius=a;
    }
    
    double calcVal(){
        
        return PI*radius*radius;
    }
};

class cylinder : public circle {
protected:
    int length;
    
public:
    cylinder();
    
    double calcVal()
    {
        return length * circle::calcVal();
        
    }
    
    
};

int main()
{
    double radius;
    
    cylinder v;
    circle c;
    
    cout<<"Enter the radius of the circle in question: "<<endl;
    cin>>radius;
    
    c.setRadius(radius);
   
    cout<<"The area of the circle is: "<<c.calcVal()<<endl;
    cout<<"The volume of the circle is:"<<v.calcVal()<<endl;
    
    
    
    return 0;
}

This is the second time you had to remind me about this....

I been programming for 9 hours today. I had to make a chess game and a address book with a bunch of switch statements. I think I should go lay down...

Thank you laser light.....