Methods Example

Here is our example from class with extensive comments

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace methodsExample
{
    class Program
    {
        /*********************
         * the point of this excercise is to show
         * how to break a program into methods
         * we have a display method and seperate
         * methods to calcualte the gas mileage
         * and the cost per mile.
         * the point of breaking a program into methods
         * is to divide the work and make it easier
         * to maintain, debug and understand.
         * Ideally each method should do one thing
         * that way it is obvious where to look if
         * something goes wrong
         * Steve Conger 10/4/2011 */

        static void Main(string[] args)
        {
            //a static method is loaded automatically
            //into RAM, but the rest of the class is not
            //so we need to "instantiate" the class
            //to load it into memory where it can be used
            Program p = new Program();
            p.Display(); //call the display method
            p.PauseIt();// call the PauseIT class
            
        }

        //void methods don't return a value
        //they just do their thing
        private void Display()
        {
            //inputs
            //just like what we did in the first assignment
            Console.WriteLine("Enter the Mileage");
             double mileage = double.Parse(Console.ReadLine());
             Console.WriteLine("Enter The Gallons");
             double gals = double.Parse(Console.ReadLine());
             Console.WriteLine("Enter The price per gallon");
             double price = double.Parse(Console.ReadLine());
            //outputs
             Console.WriteLine("Your miles per gallon is {0:F2}", 
                 CalculateGasMileage(mileage, gals));//calls the CalculateGasMileage 
            //as part of the write line. You can only do this if the
            //method returns a value

            //this is another way to do it
            //here we assign the returned result of the method
            //to a new variable
            double mpg=CalculateGasMileage(mileage, gals);

            //we can use that variable in the writeline instead of calling
            //the method again
            Console.WriteLine("Your cost per mile is {0:C}",
                CalculateCostPerMile(mpg,price));

           
        }

        //this method returns a double
        //it takes two parameters that are give values
        //when the method is called in the Display() method above
        private double CalculateGasMileage(double miles, double gallons)
        {
            double milesPerGallon;
            milesPerGallon = miles / gallons; 
            return milesPerGallon;
        }

        private double CalculateCostPerMile(double milesPerGal, double pricePerGallon)
        {
            //double costPerGallon=0;
            //this is a different way to return a value
            //you can return the equation directly
            return pricePerGallon / milesPerGal;
        }

        private void PauseIt()
        {
            Console.WriteLine("Press any key to exit");
            Console.ReadKey();
        }
    }
}