refactor: move questions into their own folder for the first 5 sections

05-write-your-first-library-package/questions/README.md

@@ -0,0 +1,104 @@
+## Which one below is correct?
+**NOTE** _There are explanations inside the answers. Even if you know the answer please try to select all of them one by one, so you can read the explanations._
+
+1. You can run a library package.
+2. In a library package there should be a function named main (func main).
+3. You can compile a library package. *CORRECT*
+4. You have to compile a library package.
+
+> **1:** You can't, but you can import it from other packages.
+>
+> **2:** In a library package, you don't have to include a main function. Because, it isn't an executable package. Only in executable packages you need a main func.
+>
+> **4:** You don't have to compile it. When you import it, it will automatically be built by the other program or library when it gets compiled or ran.
+
+
+## What do you need to export a name?
+1. You need to type it in all capital letters
+2. You need to type its first letter as a capital letter *CORRECT*
+3. You need to put it inside a function scope
+4. You need to create a new file for that name
+
+> **1:** When you do so, it will be exported, that's true, but don't do that; so I assume that this answer is not correct :)
+>
+> **2:** That's right. Then the other packages can access it.
+>
+> **3:** It should be in a package scope, not function scope.
+>
+> **4:** You don't have to do that.
+
+
+## How can you use a function from your library from an executable program?
+1. You need to export your library package first; then you can access to its imported names
+2. You need to import your library package first; then you can access to its exported names *CORRECT*
+3. You can access your library package as if it's in your executable program
+4. You can import it just by using its name
+
+> **1:** You can't export packages. All packages are already exported. Unless you put them in a directory called: "internal". But, that's an advanced topic for now.
+>
+> **2:** That's right.
+>
+> **3:** You can't access to a package from another package without importing it.
+>
+> **4:** No, you can't. You need to import it using its full directory path after GOPATH. BTW, in the near future this may change with the Go modules support.
+
+
+## In the following program, which names are exported?
+```go
+package wizard
+
+import "fmt"
+
+func doMagic() {
+    fmt.Println("enchanted!")
+}
+
+func Fireball() {
+    fmt.Println("fireball!!!")
+}
+```
+
+1. fmt
+2. doMagic
+3. Fireball *CORRECT*
+4. Println
+
+> **1:** That's just an imported package name.
+>
+> **2:** It starts with a lowercase letter; so, it's not exported.
+>
+> **3:** That's right. It starts with a capital letter.
+>
+> **4:** This isn't your function. It's already been exported in the fmt package. But, it isn't exported here.
+
+
+## In the following program, which names are exported?
+```go
+package wizard
+import "fmt"
+
+var one string
+var Two string
+var greenTrees string
+
+func doMagic() {
+    fmt.Println("enchanted!")
+}
+
+func Fireball() {
+    fmt.Println("fireball!!!")
+}
+```
+
+1. doMagic and Fireball
+2. Fireball and Two *CORRECT*
+3. Fireball, greenTrees and Two
+4. Fireball, greenTrees, one and Two
+
+> **1:** doMagic starts with a lowercase letter; so, it's not exported.
+>
+> **2:** That's right. Fireball and Two, they both start with a capital letter.
+>
+> **3:** greenTrees starts with a lowercase letter; so, it's not exported.
+>
+> **4:** one and greenTrees do not start with capital letters; so, they're not exported.