04_first_go_program.slide

# My first go program

Maximilian Wurzer
Advisory IT Architect, IBM Deutschland

## Toolbox

- Go to

.link https://play.golang.org/

- Hack away
- Questions? - Use the Webex Chat

## Exercise User

- Create a public `struct` *User* with the fields
  - id (`uint32`)
  - name (`string`)
  - surname (`string`)
  - gopher (`bool`)
- Create your personal user
  - `id` ← `1`
  - `name` and `surname` ← add your name
  - `gopher` ← obviously, `true`
- Print the result to STDOUT

## Solution User

## Result User - Solution 1

.iframe https://play.golang.org/p/j0EuuwQuigJ 550 900
//.play -edit presentation_code/firstGoProgramSolution1.go

## Result User - Solution 2

.iframe https://play.golang.org/p/uedHAieCYvT 550 900
//.play -edit presentation_code/firstGoProgramSolution2.go

## Exercise Sort

- Go comes with a sort interface which can be adapted
- `Len`, `Less`, and `Swap`

  ```
  type Interface interface {
      // Len is the number of elements in the collection.
      Len() int

      // Less reports whether the element with index i
      // must sort before the element with index j.
      Less(i, j int) bool

      // Swap swaps the elements with indexes i and j.
      Swap(i, j int)
  }
  ```

- Create a type which implements the `sort.Interface` based on a User slice
- Sort the users by ID

## Solution Sort

## Result Sort

.iframe https://play.golang.org/p/6cedRdP83V- 750 900
//.play -edit firstGoProgramSortSolution.go

## Exercise JSON

- Create a public `struct` *User* with the fields (capital letters are important)
  - ID (`uint32`)
  - Name (`string`)
  - Surname (`string`)
  - gopher (`bool`)
- Create a user and encode the user to a JSON with
  ```
  b, err := json.Marshal(m)
  ```
- Print the JSON (you will only see the fields `ID`, `Name` and `Surname`)
- Decode the JSON with
  ```
  var m User
  err := json.Unmarshal(b, &m)
  ```
  and print the Name

## Solution JSON

## Result JSON

.iframe https://play.golang.org/p/96YSbccknz8 750 900