/*
    CalcArea2.cpp
    CIS 150
    Dave Klick
    2017-01-18

    Basic numeric C++ input and output with calculations and output formatting.
    This program calculates the area of a circle given the diameter.
*/

#include <iostream>    // for: cin, cout, endl, fixed, showpoint
#include <iomanip>     // for: setprecision
using namespace std;

int main() {
    // Declare variables
    double diameter;
    double radius;
    double area;
    const double PI = 3.1415926;
    
    // Get diameter from user
    cout << "Enter the diameter: ";
    cin >> diameter;
    
    // Calculate area
    radius = diameter / 2.0;
    area = PI * radius * radius;
    
    // Display result with one digit after the decimal point
    cout << "The area of the circle is "
         << fixed << showpoint << setprecision(1)
         << area << '\n';

    cout << "Press <Enter> to continue... ";
    cin.get();
    return 0;
}