using System;

namespace MyCompiler {
    class Program {
        public static void Main(string[] args) {
            double a = null;
            // a = Convert.ToDouble(" 1.2 ");
            // a = Convert.ToDouble(" -1.2 ");
            // a = Convert.ToDouble("+1.2");
            // a = Convert.ToDouble(null);  // 0
            // a = Convert.ToDouble(" 1,200 "); // 1200
            // a = Convert.ToDouble(" 1,2 ");  // 12
            
            // a = Convert.ToDouble("");  // FormatException
            // a = Convert.ToDouble("  ");  // FormatException
            // a = Convert.ToDouble("- 1.2 ");  // FormatException
            // a = Convert.ToDouble("+ 1.2");  // FormatException
            // a = Convert.ToDouble("1 .2");  // FormatException
            // a = Convert.ToDouble("1.2a");  // FormatException
            // a = Convert.ToDouble("a1.2");  // FormatException

            Console.WriteLine(a);
        }
    }
}

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