add: slice internals exercises

16-slices/exercises/21-correct-the-lyric/main.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+)
+
+// ---------------------------------------------------------
+// EXERCISE: Correct the lyric
+//
+//  You have a slice of lyrics data of Beatles' awesome
+//  song: Yesterday. Your goal is putting the words into
+//  correct positions.
+//
+//
+// STEPS
+//
+//  1. Prepend "yesterday" to the `lyric` slice.
+//
+//  2. Put the words to the correct position in the `lyric` slice.
+//
+//  3. Print the `lyric` slice.
+//
+//
+// EXPECTED OUTPUT
+//
+//  [yesterday all my troubles seemed so far away now it looks as though they are here to stay oh i believe in yesterday]
+//
+//
+// BONUS
+//
+//   . Think about when does the append allocates a new backing array.
+//   . Then check whether your conclusions are true or not.
+//   . You can use the prettyslice package to check the backing array.
+//
+// ---------------------------------------------------------
+
+func main() {
+	// DON'T TOUCH THIS:
+	lyric := strings.Fields(`all my troubles seemed so far away oh i believe in yesterday now it looks as though they are here to stay`)
+
+	// ADD YOUR CODE BELOW:
+	// ...
+	fmt.Printf("%s\n", lyric)
+}