Using the class to find the Circle Area C + +

#include <iostream>.
#include <math.h>
using namespace Std;
Class Circle
{
Public
Double Transfer (double newr);
Double area ();
Private
Double R;
};
Double Circle::transfer (double newr)
{
R=NEWR;
}
Inline Double Circle::area ()
{
cout<<r*r*3.14<<endl;
}
int main ()
{
Circle newcircle;
Double A;
while (Cin>>a)
{
Newcircle. Transfer (a);
Newcircle.area ();
}
return 0;
}

When using classes, remember that classes and structs are the same as class circle without adding "()" and adding ";" in the back.

Using the class to find the Circle Area C + +