C#•2y ago

"FOR"

I have this code:

{
    internal class Program
    {
        static void Main(string[] args)
        {
            int[] foodPrices = { 70, 60, 55, 30, 80, 130 };
            int[] foodAmount = { 5, 10, 10, 7, 12, 15 };

            Console.WriteLine("Pizzeria!");
            Console.SetCursorPosition(0, 5);
            Console.WriteLine("Prices:");
            for (int i = 0; i < foodPrices.Length; i++)
            {
                Console.WriteLine($"\nPizza {i+1} cost {foodPrices[i]}." );
                for(int j = 0; j < foodAmount.Length; j++)
                {
                    Console.WriteLine($"Pizza {i+1} left {???}");
                }
            }
        }
    }
}

{
    internal class Program
    {
        static void Main(string[] args)
        {
            int[] foodPrices = { 70, 60, 55, 30, 80, 130 };
            int[] foodAmount = { 5, 10, 10, 7, 12, 15 };

            Console.WriteLine("Pizzeria!");
            Console.SetCursorPosition(0, 5);
            Console.WriteLine("Prices:");
            for (int i = 0; i < foodPrices.Length; i++)
            {
                Console.WriteLine($"\nPizza {i+1} cost {foodPrices[i]}." );
                for(int j = 0; j < foodAmount.Length; j++)
                {
                    Console.WriteLine($"Pizza {i+1} left {???}");
                }
            }
        }
    }
}

I somehow need to make it so that I was shown both the price of pizza and its amount. I ran into a problem: the whole array is shown to me, and not the value determined from it. How can I extract this particular value for each pizza?

34 Replies

Pobiega•2y ago

well you have a nested loop so the outer loop i will run 6 times, and the inner loop will run 6*6 times

theralseiOP•2y ago

It turns out I need to make them not nested?

Pobiega•2y ago

in fact, you just need one loop

theralseiOP•2y ago

how exactly can i do this in one loop?

Pobiega•2y ago

Well, both foodPrices and foodAmount have the exact same number of items and i is just a number, it has no direct association to either array (I'm not going to hand you the answer, but you should be able to figure it out from here on)

theralseiOP•2y ago

I'll think about it

Pobiega•2y ago

you can literally just remove the inner loop, but keep the two writelines.

theralseiOP•2y ago

I came to a working way. Is it must be like

            int[] foodPrices = { 70, 60, 55, 30, 80, 130 };
            int[] foodAmount = { 5, 10, 10, 7, 12, 15 };

            Console.WriteLine("Pizzeria!");
            Console.SetCursorPosition(0, 5);
            Console.WriteLine("Prices:");
            for (int i = 0; i < foodPrices.Length; i++)
            {
                Console.WriteLine($"\nPizza {i+1} cost {foodPrices[i]}." );
                Console.WriteLine($"Pizza {i+1} left {foodAmount[i]}");
            }

            int[] foodPrices = { 70, 60, 55, 30, 80, 130 };
            int[] foodAmount = { 5, 10, 10, 7, 12, 15 };

            Console.WriteLine("Pizzeria!");
            Console.SetCursorPosition(0, 5);
            Console.WriteLine("Prices:");
            for (int i = 0; i < foodPrices.Length; i++)
            {
                Console.WriteLine($"\nPizza {i+1} cost {foodPrices[i]}." );
                Console.WriteLine($"Pizza {i+1} left {foodAmount[i]}");
            }

Pobiega•2y ago

yep!

theralseiOP•2y ago

Thank you for your help!

Pobiega•2y ago

yw. btw, a more idiomatic C# solution to this would be to not have two arrays of prices and amounts but rather have a single array of "Pizza" class/struct that represents both values

theralseiOP•2y ago

Something like that?

string[] pizza = { "Pepperoni - 70" ...};

string[] pizza = { "Pepperoni - 70" ...};

Pobiega•2y ago

Pizza[] food = new[]
{
    new Pizza(70, 5),
    new Pizza(60, 10),
    new Pizza(55, 10),
    new Pizza(30, 7),
    new Pizza(80, 12),
    new Pizza(130, 15),
};

Console.WriteLine("Pizzeria!");
Console.SetCursorPosition(0, 5);
Console.WriteLine("Prices:");
for (int i = 0; i < food.Length; i++)
{
    Console.WriteLine($"\nPizza {i + 1} cost {food[i].Price}.");
    Console.WriteLine($"Pizza {i + 1} left {food[i].Amount}");
}

internal record struct Pizza(int Price, int Amount);

Pizza[] food = new[]
{
    new Pizza(70, 5),
    new Pizza(60, 10),
    new Pizza(55, 10),
    new Pizza(30, 7),
    new Pizza(80, 12),
    new Pizza(130, 15),
};

Console.WriteLine("Pizzeria!");
Console.SetCursorPosition(0, 5);
Console.WriteLine("Prices:");
for (int i = 0; i < food.Length; i++)
{
    Console.WriteLine($"\nPizza {i + 1} cost {food[i].Price}.");
    Console.WriteLine($"Pizza {i + 1} left {food[i].Amount}");
}

internal record struct Pizza(int Price, int Amount);

something like this we can make our own types and you should be taking advantage of that 🙂

theralseiOP•2y ago

I'm just a beginner in C#, and I didn't even think about a solution like that. catshrug

Anyways, thank you!

Pobiega•2y ago

Thats fine! Im just telling you the "idiomatic" solution

theralseiOP•2y ago

                    case 1:
                        Console.WriteLine("Pizza name: ");
                        userPizzaInput = Console.ReadLine();
                        if(userPizzaInput != food.Name)
                        break;

                    case 1:
                        Console.WriteLine("Pizza name: ");
                        userPizzaInput = Console.ReadLine();
                        if(userPizzaInput != food.Name)
                        break;

Here another problem come. I have the same code, I just added a new string parameter called name. Since I have a pizzeria, you have to buy pizza in a pizzeria, so I wanted to make such a mechanic. But just by calling food in the condition, I will not be able to get "Name" from it. How can i do this?

Pobiega•2y ago

can you show your full code? or did you base this on my code above?

theralseiOP•2y ago

Yeah

Pobiega•2y ago

well, food is not just one pizza, its all of them so you need to see if one of them match the provided name you could do this with a loop, like before, but there are some very helpful methods for this kind of operation already

theralseiOP•2y ago

I need to make sure that I can't buy pizza that doesn't exist.

Pobiega•2y ago

sure

theralseiOP•2y ago

I hate the translator, lol. I mean I want to make that I can't but pizza that doesn't exist But I'll think you understood me

Pobiega•2y ago

I understand what you are trying to say, np

Pizza[] food =
{
    new Pizza("One", 70, 5),
    new Pizza("Two", 60, 10),
    new Pizza("Three", 55, 10),
    new Pizza("Four", 30, 7),
    new Pizza("Five", 80, 12),
    new Pizza("Six", 130, 15),
};

Pizza[] food =
{
    new Pizza("One", 70, 5),
    new Pizza("Two", 60, 10),
    new Pizza("Three", 55, 10),
    new Pizza("Four", 30, 7),
    new Pizza("Five", 80, 12),
    new Pizza("Six", 130, 15),
};

internal class Pizza
{
    public Pizza(string name, int price, int amount)
    {
        Name = name;
        Price = price;
        Amount = amount;
    }

    public string Name { get; set; }
    public int Price { get; set; }
    public int Amount { get; set; }
}

internal class Pizza
{
    public Pizza(string name, int price, int amount)
    {
        Name = name;
        Price = price;
        Amount = amount;
    }

    public string Name { get; set; }
    public int Price { get; set; }
    public int Amount { get; set; }
}

Console.WriteLine("Pizza name: ");
var userPizzaInput = Console.ReadLine();
var selectedPizza = food.FirstOrDefault(x => x.Name == userPizzaInput);
if (selectedPizza is null)
{
    Console.WriteLine("No pizza with that name.");
}

Console.WriteLine("Pizza name: ");
var userPizzaInput = Console.ReadLine();
var selectedPizza = food.FirstOrDefault(x => x.Name == userPizzaInput);
if (selectedPizza is null)
{
    Console.WriteLine("No pizza with that name.");
}

I changed Pizza a bit, since we'll likely want to change the value of Amount in the future and record struct would make that... awkward. Better to use a normal class here the real magic is these lines:

var selectedPizza = food.FirstOrDefault(x => x.Name == userPizzaInput);
if (selectedPizza is null)

var selectedPizza = food.FirstOrDefault(x => x.Name == userPizzaInput);
if (selectedPizza is null)

theralseiOP•2y ago

I have not met var. I understand that it can store data of any type?

Pobiega•2y ago

no, it just means "figure out the type for me" in this case, that type is Pizza?

theralseiOP•2y ago

Oh well, I take it that's pretty effective.

Pobiega•2y ago

its entirely optional, I personally use it a lot but I can see why a beginner would prefer to type out their types 🙂

theralseiOP•2y ago

Could you explain how these lines work?

Pobiega•2y ago

the important part is understanding that there is no difference in type safety here - they are both the exact same thing being compiled sure FirstOrDefault will return the first item in the collection that matches the predicate function the predicate being x => x.Name == userPizzaInput here thats a "lambda function", here its a function that takes in a Pizza x and returns true or false the first item to return true will be returned by FirstOrDefault if the end of the collection is reached and no item has been returned, it will return default, in this case null (because Pizza is a class)

theralseiOP•2y ago

That's really interesting. Thank you!

Pobiega•2y ago

There are TONS of similar functions! First, Any, All, Single, Where, OrderBy etc

theralseiOP•2y ago

By the way, I didn’t understand how Pizza turned into x, and why it’s x at all.

Angius•2y ago

x => x.Name == userPizzaInput

x => x.Name == userPizzaInput

is, essentially, a shorthand for

static bool Whatever(Pizza x)
{
    return x.Name == userPizzaInput;
}

static bool Whatever(Pizza x)
{
    return x.Name == userPizzaInput;
}

theralseiOP•2y ago

got it! thanks!

Gaming

Programming

"FOR"