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Part 3 – Built-in types
Part 4 – String type
Part 5 – Operators
In this video, we will discuss
1. Nullable types in C#
2. Null Coalescing Operator ??
In C# types are divided into 2 broad categories.
Value Types – int, float, double, structs, enums etc
Reference Types – Interface, Class, delegates, arrays etc
By default value types are non nullable. To make them nullable use ?
int i = 0 (i is non nullable, so “i” cannot be set to null, i = null will generate compiler error)
int? j = 0 (j is nullable int, so j=null is legal)
Nullable types bridge the differences between C# types and Database types
Program without using NULL coalescing operator
using System;
class Program
{
static void Main()
{
int AvailableTickets;
int? TicketsOnSale = null;
if (TicketsOnSale == null)
{
AvailableTickets = 0;
}
else
{
AvailableTickets = (int)TicketsOnSale;
}
Console.WriteLine(“Available Tickets={0}”, AvailableTickets);
}
}
The above program is re-written using NULL coalescing operator
using System;
class Program
{
static void Main()
{
int AvailableTickets;
int? TicketsOnSale = null;
//Using null coalesce operator ??
AvailableTickets = TicketsOnSale ?? 0;
Console.WriteLine(“Available Tickets={0}”, AvailableTickets);
}
}
[youtube https://www.youtube.com/watch?v=HuLJbiqpIM0?rel=0&showinfo=0]
