Question

Taking beginning Data Structures in C# class, trying to make a searchable arraylist of a string and an int referenced together (name and number).I need to be able to search for the name, and retrieve both the name and the number it’s attached to. I was told I can use an arraylist of structs, but have never used structs. Any simple explanation how, or a better way?

Thank you in advance.

Answer 1

You should probably be using something like a hash for this as an ArrayList of structs is a bit square peg round hole.

You declare a struct just like a calss.

public struct Foo {
    public String Bar { get; set; }
    public Int32  Biz { get; set; }
}

And you can make an array list of then as you would with any type

var list = new ArrayList();
list.add(object);

The other issue here is that ArrayList isn’t generic, it will cast everything to Object which means you will have to cast everything back to type Foo to work with it.

var foo = (Foo)list.item(0);

You would be much better off, if you have to go the route of List instead of Hash using a generic list class like List and declaring its type;

var list = List<Foo>();
var foo = new Foo { Bar = "Hello World", Biz = 1 };
list.add(foo);

As for searching a list, I prefer to use the LINQ methods, because they are quick to code and easy to read.

var matches = list.Where( x => x.Biz > 1 );

But if you cannot do that then iteration always works

var matches = new List<Foo>();
foreach ( var foo in list ) {
    if ( list.Biz > 1 ) {
        matches.add(foo);
    }
}