Using Custom Types

// Build a collection of customers who are millionaires
public class Customer
{
    public string Name { get; set; }
    public double Balance { get; set; }
    public string Bank { get; set; }
}

public class Program
{
    public static void Main() {
        List<Customer> customers = new List<Customer>() {
            new Customer(){ Name="Bob Lesman", Balance=80345.66, Bank="FTB"},
            new Customer(){ Name="Joe Landy", Balance=9284756.21, Bank="WF"},
            new Customer(){ Name="Meg Ford", Balance=487233.01, Bank="BOA"},
            new Customer(){ Name="Peg Vale", Balance=7001449.92, Bank="BOA"},
            new Customer(){ Name="Mike Johnson", Balance=790872.12, Bank="WF"},
            new Customer(){ Name="Les Paul", Balance=8374892.54, Bank="WF"},
            new Customer(){ Name="Sid Crosby", Balance=957436.39, Bank="FTB"},
            new Customer(){ Name="Sarah Ng", Balance=56562389.85, Bank="FTB"},
            new Customer(){ Name="Tina Fey", Balance=1000000.00, Bank="CITI"},
            new Customer(){ Name="Sid Brown", Balance=49582.68, Bank="CITI"}
        };
    }
}

/*
    Given the same customer set, display how many millionaires per bank.
    Ref: https://stackoverflow.com/questions/7325278/group-by-in-linq

    Example Output:
    WF 2
    BOA 1
    FTB 1
    CITI 1
*/