#include <iostream>
#include <iomanip>       // for setw
#include <cmath>         // for sqrt
using namespace std;

// Owen Astrachan
// nested loops to print wind-chill chart
//
// idea: Programming with Class by Kamin and Reingold, McGraw-Hill
// formula for wind-chill from
// UMAP Module 658, COMAP, Inc., Lexington, MA 1984, Bosch and Cobb

double WindChill(double temperature, double windSpeed);

int main()
{
    const int WIDTH = 5;
    const int MIN_TEMP = -40;
    const int MAX_TEMP = 50;
    const string LABEL = "deg. F: ";
    int temp,wind;

    // print column headings
    
    cout << LABEL;
    for(temp = MAX_TEMP; temp >= MIN_TEMP; temp -=10)
    {   cout << setw(WIDTH) << temp;
    }
    cout << endl << endl;

    // print table of wind chill temperatures
    
    for(wind = 0; wind <= MAX_TEMP; wind += 5) // row heading
    {   cout  << wind << " mph:\t";
        
        for (temp = MAX_TEMP; temp >= MIN_TEMP; temp -= 10)  // print the row
        {   cout << setw(WIDTH) << int(WindChill(temp,wind));
        }
        cout << endl;
    }
    return 0;
}

double WindChill(double temperature, double windSpeed)
// precondition: temperature in degrees Fahrenheit
// postcondition: returns wind-chill index/comparable temperature
{
    if (windSpeed <= 4)          // low wind, temperature unaltered
    {   return temperature;
    }
    else if (windSpeed <= 45)    // high wind
    {   return
           91.4 - (10.45 + 6.69*sqrt(windSpeed) - 0.447 * windSpeed) *
           (91.4 - temperature)/22.0;
    }
    else
    {   return (1.6 * temperature - 55.0);
    }
}