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ExG.Nullable/Program.cs

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+internal class Program
+{
+    private static void Main(string[] args)
+    {
+        MyClass cls = new();
+        cls.NullableTest();
+    }
+
+}
+
+class MyClass
+{
+    double _Sum = 0;
+    DateTime _Time;
+    bool? _Selected;
+
+    public void CheckInput(int? i, double? d, DateTime? time, bool? selected)
+    {
+        if (i.HasValue && d.HasValue)
+            this._Sum = (double)i.Value + (double)d.Value;
+
+        // time값이 있는 체크.
+        if (!time.HasValue)
+            throw new ArgumentException();
+        else
+            this._Time = time.Value;
+
+        // 만약 selected가 NULL이면 false를 할당
+        this._Selected = selected ?? false;
+    }
+    public void NullableTest()
+    {
+        int? a = null;
+        int? b = 0;
+        int result = Nullable.Compare<int>(a, b);
+        Console.WriteLine(result); //결과 -1
+
+        double? c = 0.01;
+        double? d = 0.0100;
+        bool result2 = Nullable.Equals<double>(c, d);
+        Console.WriteLine(result2); //결과 true
+    }
+}