What is wrong with this c++ code
// this program finds the length of a fence needed to enclose a circular garden and the area
#include
using namespace std;
int main()
{
const double PI=3.1415;
double area, //area of the garden
length, //length of the fence
radius , //radius of garden
circumference; //circumference of garden
cout<<"enter area of garden: ";
cin>> area;
area= PI * radius * radius;
circumference = 2 * PI * radius;
cout<<"n";
cout<<"the area is " << setw(11) area << "n";
cout<<"the length of fence is " <cout<<"the radius is " <
"nnn";
return 0;
}