Here are simple c# programs Hello World using System; class Program { static void Main() { Console.WriteLine("Hello, World!"); } } Add Two Numbers using System; class Program { static void Main() { int a = 10; int b = 20; int sum = a + b; Console.WriteLine("Sum = " + sum); } } Find Even or Odd Number using System; class Program { static void Main() { int num = 7; if (num % 2 == 0) Console.WriteLine("Even"); else Console.WriteLine("Odd"); } } Swap Two Numbers using System; class Program { static void Main() { int a = 5, b = 10; int temp = a; a = b; b = temp; Console.WriteLine("a = " + a); Console.WriteLine("b = " + b); } } Find Largest of Three Numbers using System; class Program { static void Main() { int a = 10, b = 25, c = 15; int largest = a; if (b > largest) largest = b; if (c > largest) largest = c; Console.WriteLine("Largest = " + largest); } }