查找热量最高的产品的方法c＃

Question

I have to find the product with the highest number of calories. My program knows to print all the products with their calories and now I'm working how to print only the product with the highest number.

I have my class Food:

 class Food : Product{
 private NutritionalData nutritionalData;
    private DateTime expirationTerm;
    public FoodCategory Category;

    public Food(int ProductId, string SKU, string Name, decimal Price, string Description, string Producer,
        NutritionalData nutritionalData, FoodCategory Category, DateTime expirationTerm)
        : base(ProductId, SKU, Name, Price, Description, Producer)
    {

        this.nutritionalData = nutritionalData;
        this.Category = Category;
        this.expirationTerm = expirationTerm;
    }
    public Food() { }
 public NutritionalData GetNutritionalData()
    {
        return nutritionalData;
    }
    public int GetCalories()
    {
        return nutritionalData.Calories;
    }

    public override void PrintCalories()
    {

            int i = this.GetCalories();
            Console.WriteLine("Product: {0}, Calories: {1},ProductId: {2}", this.GetName(), i, this.GetProductId());

    }
    }

//here I have some class and some struct but there is no relation with my idea so I don't put here all the stuff. And here is the main:

class Program
{
    static void Main(string[] args)
    {
        Product f = new Food(1, "a", "Food", 15, "Good Quality", "Sana",new NutritionalData(2,12,1,3,2) //(2=calories,12=,1,3,2=doens't matter,
            FoodCategory.Meat, new DateTime(2015,4,12));
        Product f1 = new Food(2, "v", "Pizza1", 2, "Bad Quality", "Ariel", new NutritionalData(8, 17, 5, 3, 2),
            FoodCategory.Meat, new DateTime(2015, 4, 11));
        f.PrintCalories();
        f1.PrintCalories();
    }
}
}

Sorry if you don't understand many things but first I wanted to put here only a few things but then I thought you wouldn't have understood nothing.What's important is that I don't know how to verify all the products, for example if I have the first one f, it has nr of calories=2, how can I verify the following product if has a number of calories greater of smaller than this one and so on? With the method GetCalories I return the product with the calories but now I'm stucked. Some ideas? If you don't understand what I want to do please tell me.Thank you.

Update: I tried something but without result:

 public override void PrintCalories()
    {
        int max = 0;
        int i = this.GetCalories();
        if (i > max)
        {
            Console.WriteLine("Product: {0}, Calories: {1},ProductId: {2}", this.GetName(), i, this.GetProductId());
        }
        else
            Console.WriteLine("Product: {0}, Calories: {1},ProductId: {2}", this.GetName(), max, this.GetProductId());
        max = i;

    }

Answer 1

In order for you to print the product with the highest calories, you need to keep track of that in some way as you're dealing with your new product instances.

I would suggest you interrogate each instance and maintain a reference to the instance that has the highest calories value. For example:

var highestCaloriesSoFar = f;  // store your first instance since you haven't seen any others yet.

// --- whatever code you ultimately have in between getting each instance. 

if (nextInstance.NutritionData.Calories > highestCaloriesSoFar.NutritionData.Calories) 
    highestCaloriesSoFar = nextInstance;

Then you could just print that instance at the end.

Now, I'm saying this without actually knowing how you're going to ultimately code this because it looks like what you have in your Main is a work in progress. It seems unlikely that you are just going to hard-code, as it were, a bunch of instances directly in your main method and more likely that you are going to receive them or build them externally and then produce the output from that collection. Therefore, you could have a method utilizing the code above that takes a collection of Food instances and returns the one with the highest calories:

private static Food GetHighestCalories(IEnumerable<Food> fromCollection)
{
    Food highestCaloriesSoFar = null;

    foreach (Food nextInstance in fromCollection)
    {
        if(highestCaloriesSoFar != null)
        {
            if (nextInstance.NutritionData.Calories > highestCaloriesSoFar.NutritionData.Calories) 
                highestCaloriesSoFar = nextInstance;
        }
        else // first loop iter.
        {
            highestCaloriesSoFar = nextInstance;
        }
    }

    return highestCaloriesSoFar;
}