expected primary-expression before '*'? - c++

Question

I have looked through all of these and am relatively new to coding c++ and just don't know what I am missing. Any idea's?
My error occurs at line 45 "return pi * (Radius * Radius);" I am almost positive that the syntax for that line is correct but why am i getting compile errors.
#include <iostream>
#include <cstdlib>
using namespace std;
const double pi = 3.14159;
class Rectangle
{
protected:
float length, width;
public:
Rectangle(): length(0), width(0)
{
cout<<"Enter length: "; cin>>length;
cout<<"Enter width: "; cin>>width;
}
};
class Circle
{
protected:
float Radius;
public:
double radius;
Circle(): Radius(0)
{
cout<<"Enter Radius: "; cin>>Radius;
}
};
class Area : public Rectangle
{
public:
float getArea()
{
return length*width;
}
};
class Radius : public Circle
{
public:
float getRadius()
{
return pi * (Radius * Radius);
}
};
int main()
{
char choice;
for (int i = 0; i < 4; i++) //loop statement
{
cout << "Program to Find Area of a Square and Circle" << endl << //selection of which calculation to run
"Enter S for square square." << endl <<
"Enter C for circle." << endl <<
"Enter Q to Quit the program." << endl << endl <<
"Enter an option above: ";
cin >> choice;
switch(choice)
{
//Square option:
case 'S':
case 's': {
cout<<"Enter data for rectangle to find area.\n";
Area a;
cout<<"Area = "<<a.getArea()<<" square\n\n";
break;}
//Circle option:
case 'C':
case 'c': {
cout<<"Enter data for circle to find radius.\n";
Radius c;
cout<<"Radius = "<<c.getRadius()<<" meter\n\n";
break;}
//Quit option:
case 'Q':
case 'q': {
cout << "Thank you for using Area Application" << endl << endl;
system("PAUSE");
return EXIT_SUCCESS;
break;}
//default option binds to a non-selected choice function:
default:
cout << choice << " is not a valid selection." << endl;
cout << "Select a valid shape choice: S or C" << endl << endl;
break;
}
}
cout << "Press enter to continue ..." << endl;
return EXIT_SUCCESS;
}
Thanks
David

Answer 1

Now I see you have a member in base class which has a name Radius which is the same as in derived class, this is what is causing an error. The solution is to qualify it with base class name:
change:
return pi * (Radius * Radius);
to:
return pi * (Circle::Radius * Circle::Radius);
this additonal: double radius; is probably from some testing - right?
[edit]
From design point of view the existance of class Radius : public Circle makes little sense, it should be fine to just use Circle to get its radious.

Answer 2

#include <iostream>
#include <cstdlib>
using namespace std;
const double pi = 3.14159;
class Rectangle
{
protected:
float length, width;
public:
Rectangle(): length(0), width(0)
{cout<<"Enter length: "; cin>>length;cout<<"Enter width: "; cin>>width;}
float getArea(){return length*width;}
};
class Circle
{
protected:
float Radius;
public:
Circle(): Radius(0) {cout<<"Enter Radius: "; cin>>Radius;}
float getRadius() {return pi * (Radius * Radius);}
};
int main()
{
char choice;
for (int i = 0; i < 4; i++) //loop statement
{
cout << "Program to Find Area of a Square and Circle" << endl << //selection of which calculation to run
"Enter S for square square." << endl <<
"Enter C for circle." << endl <<
"Enter Q to Quit the program." << endl << endl <<
"Enter an option above: ";
cin >> choice;
switch(choice)
{
//Square option:
case 'S':
case 's': {
cout<<"Enter data for rectangle to find area.\n";
Rectangle a;
cout<<"Area = "<<a.getArea()<<" square\n\n";
break;}
//Circle option:
case 'C':
case 'c': {
cout<<"Enter data for circle to find radius.\n";
Circle c;
cout<<"Radius = "<<c.getRadius()<<" meter\n\n";
break;}
//Quit option:
case 'Q':
case 'q': {
cout << "Thank you for using Area Application" << endl << endl;
system("PAUSE");
return EXIT_SUCCESS;
break;}
//default option binds to a non-selected choice function:
default:
cout << choice << " is not a valid selection." << endl;
cout << "Select a valid shape choice: S or C" << endl << endl;
break;
}
}
cout << "Press enter to continue ..." << endl;
return EXIT_SUCCESS;
}