restructure: arrays and slices

16-slices/questions/1-slices-vs-arrays.md

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+# Slices vs Arrays Quiz
+
+## Why you want to use a slice instead of an array?
+1. I like arrays more
+2. I want to create a dynamic collection, so I need an array
+3. A slice's length is dynamic, so I can create dynamic collections *CORRECT*
+
+
+## Where does the length of a slice belong to?
+1. Compile-Time
+2. Runtime *CORRECT*
+3. Walk-Time
+4. Sleep-Time
+
+> **2:** A slice's length is not a part of its type. So its length can change at runtime.
+
+
+## Which function call below is correct?
+```go
+// Let's say there's a function like this.
+func sort(nums []int) {
+    // ...
+}
+```
+1. sort([...]int{3, 1, 6})
+2. sort([]int32{3, 1, 6})
+3. sort([]int{3, 1, 6}) *CORRECT*
+
+> **1:** You can't call the sort function using an array. It expects an int slice.
+> 
+> **2:** You can't call the sort function using an int32 slice. It expects an int slice.
+> 
+> **3:** That's right! You can pass an int slice to the sort function.
+
+
+## What is the zero value of this slice?
+```go
+var tasks []string
+```
+1. 0
+2. 1
+3. nil *CORRECT*
+4. unknown
+
+> **3:** This is a nil slice. Unlike an array, a slice's zero value is nil.
+
+
+## What does this code print?
+```go
+var tasks []string
+fmt.Println(len(tasks))
+```
+
+1. 0 *CORRECT*
+2. 1
+3. nil
+4. It doesn't work.
+
+> **1:** Yes, you can use the len function on a nil slice. It returns 0 because the slice doesn't contain any elements yet.
+
+
+## What does this code print?
+```go
+var tasks []string
+fmt.Println(tasks[0])
+```
+
+1. 0
+2. 1
+3. nil
+4. It doesn't work. *CORRECT*
+
+> **4:** You can't get an element that does not exist. A nil slice does not contain any elements.
+
+
+## Which declaration below is a correct slice declaration?
+1. [...]int{}
+2. [2]string{"hello", "world"}
+3. []string{"hello", "world"} *CORRECT*
+4. string[2]{"hello", world"}
+
+
+## This code doesn't work, why?
+```go
+colors := []string{"red", "blue", "green"}
+tones := []string{"dark", "light"}
+
+if colors == tones {
+    // ...
+}
+```
+
+1. The slices have different lengths
+2. If statement doesn't contain any statements
+3. Slices cannot be compared *CORRECT*
+
+> **3:** That's right! A slice value can only be compared to a nil value.
+
+
+## What is the length of this slice?
+```go
+[]uint64{}
+```
+
+1. 64
+2. 1
+3. 0 *CORRECT*
+4. Error
+
+> **3:** That's right. This is an empty slice, it doesn't contain any elements.
+
+
+## What is the length of this slice?
+```go
+[]string{"i'm", "going", "to", "stay", "\"here\""}
+```
+
+1. 0
+2. 1
+3. 2
+4. 3
+5. 4
+6. 5 *CORRECT*