using System;
namespace App{
    class MyClass{
        public static void Main(string[] args){
            char a='A';
            int b=a;
            Console.WriteLine(b);//65
            Console.WriteLine(a);//A
        }
    }
}

            double a=10.902;
            int b=(int) a;
            Console.WriteLine(b);//10
            Console.WriteLine(a);//10.902

using System;
namespace App{
    class MyClass{
        public static void Main(string[] args){
            //string str= Convert.ToString(null);
            bool str= Convert.ToString(null)==null;//True
            Console.WriteLine(str);
        }
    }

            bool str= Convert.ToString("")=="";//True
            Console.WriteLine(str);