using System;
public class Test
{
public static void Main()
{
string s = null;
if (s == "abc")
{
Console.WriteLine("equals abc");
}
else if (s == "")
{
Console.WriteLine("equals empty");
}
else if ("123" == s)
{
Console.WriteLine("equals 123");
}
else
{
Console.WriteLine("not equal");
}
s = "";
string b = null;
if (s.CompareTo(b) == 0)
{
Console.WriteLine("equals null");
}
else
{
Console.WriteLine("s.CompareTo(b) produces: " + s.CompareTo(b));
}
}
}
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