Section 1.11 - equivalent lines are not exactly equivalent

[gregsdennis]

First, thanks for this! I recognize that putting a lesson plan together is a lot of work.

In Section 1.11, you're introducing fmt.Println(), and you compare it to C#'s Console.WriteLine(). While the functions perform the same task (output to console), I think it's worth mentioning that fmt.Println() handles the values a bit more nicely.

For example, you have the following text:

The following are equivalent:

Go

  fmt.Println(ids)

C#

  Console.WriteLine(ids);

But ids is an array, and the golang docs say this:

For compound objects, the elements are printed using these rules, recursively, laid out like this:

struct:             {field0 field1 ...}
array, slice:       [elem0 elem1 ...]
maps:               map[key1:value1 key2:value2 ...]
pointer to above:   &{}, &[], &map[]

In short, fmt.Println() will automatically format complex types, like custom objects and arrays. In C#, you need to use a serializer or other formatter; otherwise you'll just get the type name.

[gregsdennis]

Also appears in lesson 13.

The following are equivalent:
Go

  fmt.Printf("%d: %v\n", p.ID, p)

C#

  Console.Write("{0:d}: {1}\n", p.ID, p);

where Console.Write() doesn't automatically format object types.

[jeremybytes]

Thanks Greg. I'll need to take a closer look at this. The intent of the comparison is that both fmt.Println and Console.Write use the default formatter for whatever they output. In the first example, you are correct that the array would not be formatted in the C# version. In the second example, the output of "p" is correct in C# because the Person type has a ToString override (based on the C# code that was used as a comparison, but there's no way for you to know that 🤭).

I am not sure how much effort I can put into the CodeTour at this point. I like the idea of CodeTour, but the editing experience is not as easy as I would like it to be. Also, this demo is a bit out of date as it was written before Go had generics. I do have an updated walkthrough that I've used for live presentations, but it is not currently in a consumable format. You can take a look at it here if you like: Walkthrough.md. This walkthrough builds the application from scratch and I use it to talk about similarities and differences between Go and C#.