Compile time: string my_value = Console.ReadLine(); int i = my_value;
A string value can't be assigned a variable of type int, so the compiler knows for sure at compile time that this code has a problem Run time: string my_value = Console.ReadLine(); int i = int.Parse(my_value); Here the outcome depends on what string was returned by ReadLine(). Some values can be parsed to an int, others can't. This can only be determined at run time. More on... [http://net-informations.com/python/iq/checking.htm](http://net-informations.com/python/iq/checking.htm)
