Übung 8-01

#include <iostream>
#include <cmath>

using namespace std;

double Kreisf(double x);

const double pi = 3.1415926535;

int main()
{
    double a;
    cout << "Radius eingeben" << endl;
    cin >> a;
    cout << Kreisf(a) <<  endl;
    return 0;
}

double Kreisf(double x) {
    x = pi * pow(x,2);
    return x;
}