Rounding multiple double numbers to two decimal places-CodePudding

i'm new to programming, i decided to try and write this program, as an exercise, in the end it works fine without issues.

Below the third comment I'm initializing a variable performing calculation, after that statement, I'm rounding the value to two decimal places. Looking at that piece of code block, I'm repeating the two lines 7 times, and I'm thinking there is probably a better way to shorten that block of code.

double weightEarth, earthG, mercuryG, marsG, uranusG, venusG, saturnG, neptuneG, jupiterG;
            
//Assigning gravity force value corresponding to each planet
earthG = 9.81;
mercuryG = 3.7;
marsG = 3.711;
uranusG = 8.69;
venusG = 8.87;
saturnG = 10.44;
neptuneG = 11.15;
jupiterG = 24.79;

//Receive user input
Console.ForegroundColor = ConsoleColor.Green;
Console.WriteLine("This program will calculate how much you will weight on all planets");
Console.Write("Type in your weight in kg: ");
weightEarth = double.Parse(Console.ReadLine());

 //Calculating mass of object by dividing and gravitional force by multiplication
double weightMercury = (weightEarth / earthG) * mercuryG;
    weightMercury = Math.Round(weightMercury, 2);
double weightMars = (weightEarth / earthG) * marsG;
    weightMars = Math.Round(weightMars, 2);
double weightUranus = (weightEarth / earthG) * uranusG;
    weightUranus = Math.Round(weightUranus, 2);
double weightVenus = (weightEarth / earthG) * venusG;
    weightVenus = Math.Round(weightVenus, 2);
double weightSaturn = (weightEarth / earthG) * saturnG;
    weightSaturn = Math.Round(weightSaturn, 2);
double weightNeptune = (weightEarth / earthG) * neptuneG;
    weightNeptune = Math.Round(weightNeptune, 2);
double weightJupiter = (weightEarth / earthG) * jupiterG;
    weightJupiter = Math.Round(weightJupiter, 2);

Console.ForegroundColor = ConsoleColor.Blue;
Console.WriteLine("\r\nYou weight:");
Console.WriteLine(weightMercury   "kg on Mercury");
Console.WriteLine(weightMars   "kg on Mars");
Console.WriteLine(weightUranus   "kg on Uranus");
Console.WriteLine(weightVenus   "kg on Venus");
Console.WriteLine(weightSaturn   "kg on Saturn");
Console.WriteLine(weightNeptune   "kg on Neptune");
Console.WriteLine(weightJupiter   "kg on Jupiter");

Console.ReadKey();

CodePudding user response：

Depending on how far you want to go, there are some concepts you can follow.

The first one is Don't Repeat Yourself (DRY). You could extract the weight calculation to a new method, like,

private static double GetWeightForPlanet(double weightEarth, double earthG, double planetG)
{
      double weightPanet = (weightEarth / earthG) * planetG;
      weightPanet = Math.Round(weightPanet, 2);
      return weightPanet;
}

Now your program will look like this,

//Calculating mass of object by dividing and gravitional force by multiplication
double weightMercury = GetWeightForPlanet(weightEarth, earthG, mercuryG);
double weightMars = GetWeightForPlanet(weightEarth, earthG, marsG);
double weightUranus = GetWeightForPlanet(weightEarth, earthG, uranusG);
double weightVenus = GetWeightForPlanet(weightEarth, earthG, venusG);
double weightSaturn = GetWeightForPlanet(weightEarth, earthG, saturnG);
double weightNeptune = GetWeightForPlanet(weightEarth, earthG, neptuneG);
double weightJupiter = GetWeightForPlanet(weightEarth, earthG, jupiterG);

Console.ForegroundColor = ConsoleColor.Blue;
Console.WriteLine("\r\nYou weight:");
Console.WriteLine(weightMercury   "kg on Mercury");
Console.WriteLine(weightMars   "kg on Mars");
Console.WriteLine(weightUranus   "kg on Uranus");
Console.WriteLine(weightVenus   "kg on Venus");
Console.WriteLine(weightSaturn   "kg on Saturn");
Console.WriteLine(weightNeptune   "kg on Neptune");
Console.WriteLine(weightJupiter   "kg on Jupiter");

There is still some repeating code, but I can see some common data patterns. Maybe a data structure will help; let's introduce the concept (class) Planet,

public class Planet
{
    public string Name { get; set; }
    public double Gforce { get; set; }
}

Your code will look like this,

double earthG = 9.81, weightEarth;

var planets = new List<Planet>
{
       new Planet { Name = "Mercury", Gforce = 3.7 },
       new Planet { Name = "Mars", Gforce = 3.711},
       new Planet { Name = "Uranus", Gforce = 8.69 },
       new Planet { Name = "Saturn", Gforce = 10.44 },
       new Planet { Name = "Neptune", Gforce = 11.15 },
       new Planet { Name = "Venus", Gforce = 8.87 },
       new Planet { Name = "Jupiter", Gforce = 24.79 }
};

//Receive user input
Console.ForegroundColor = ConsoleColor.Green;
Console.WriteLine("This program will calculate how much you will weight on all planets");
Console.Write("Type in your weight in kg: ");
weightEarth = double.Parse(Console.ReadLine());

Console.ForegroundColor = ConsoleColor.Blue;

Console.WriteLine("\r\nYou weight:");

foreach (var planet in planets)
{
     Console.WriteLine($"{GetWeightForPlanet(weightEarth, earthG, planet.Gforce)} kg on {planet.Name}");
}

I can keep going but probably stop here. This is for demonstration purposes only not for production code. Be kind on code reviews :)