#include <iostream>
#include <cmath>
using namespace std;

// function to calculate "something" using this equation:
//
//           3
//   f(x) = x  + 10x + 5
//
double f( double x )
{
    // body of the function
    double result = pow( x, 3 ) + 10 * x + 5;

    return result;
}

//           2    2
// g(x,y) = x  - y
//
double g( double x, double y )
{
    return pow( x, 2 ) - pow( y, 2 );
}

int main()
{
    cout << "Enter a number for x: ";
    double x;
    cin >> x;

    double answer = f( x );
    cout.precision( 8 );  // display exactly 8 digits
    cout << "Applying f(x), the result is " << answer
         << endl;

    cout.setf( ios_base::fixed );
    cout.precision( 5 );  // display 5 digits after
                          //   the decimal point
    cout << "Applying f(x), the result is " << answer
         << endl;

    double r = g( x, answer );
    cout << "Applying g(x, f(x)), the result is "
         << r << endl;

    return 0;
}