Can I do an ID foreach instance of class?-CodePudding

I'm a newbie in c#. I am just trying to do an ID for each instance in class Person.

class Person
    {
        public Person(string name, int age)
        {
            countPersons  ;
            this.name = name;
            this.age = age;
        }

        public string name { private get; set; }
        public int age { private get; set;}
        private static int countPersons { get; set; }
        
        public void GetNameAndAge()
        {
            Console.WriteLine($"Player name: {name ?? "unknown"} | Player age: {age}");
        }
        public void GetInfo()
        {
            Console.WriteLine($"Player name: {name ?? "unknown"} | Player age: {age}\nId: {countPersons}");
        }

    }

I want every class instance to have an id that starts from one (one, two, three, etc.)

class Program
    {
        public static void Main(string[] args)
        {
            var player1 = new Person("David", 31);
            var player2 = new Person("Brad", 23);
            var player3 = new Person("Michael", 26);

            player1.GetNameAndAge();
            player1.GetInfo();
            player2.GetInfo();
            player3.GetInfo();
        }
    }

But at the end of the program, the ID for everyone is 3... (The variable countPersons is my ID)

CodePudding user response：

You have to hold that in variable or property.

class Person
    {
        public Person(string name, int age)
        {
            id = countPersons  ;
            this.name = name;
            this.age = age;
        }
        int id;
        public string name { private get; set; }
        public int age { private get; set;}
        private static int countPersons { get; set; }
        
        public void GetNameAndAge()
        {
            Console.WriteLine($"Player name: {name ?? "unknown"} | Player age: {age}");
        }
        public void GetInfo()
        {
            Console.WriteLine($"Player name: {name ?? "unknown"} | Player age: {age}\nId: {id}");
        }

    }

Note:

Static will increase with each instance creation.
id will hold that vlaue.

CodePudding user response：

You need to store the id as property like

public class Person
{
    public Person(int id, string name, int age)
    {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    public int id { private get; set; }
    public string name { private get; set; }
    public int age { private get; set; }
    private static int countPersons { get; set; }

    public void GetNameAndAge()
    {
        Console.WriteLine($"Player name: {name ?? "unknown"} | Player age: {age}");
    }
    public void GetInfo()
    {
        Console.WriteLine($"Player name: {name ?? "unknown"} | Player age: {age}\nId: {countPersons}");
    }

}

CodePudding user response：

This is happening because you are using a static countPersons and assigning to that.

Instead you could use a for loop in the main function and pass that index in to the Person constructor. This way you would have IDs like 0,1,2,…