This Go code demonstrates how slices in Go can be...

This Go code demonstrates how slices in Go can be manipulated by altering their length and capacity using slicing operations. Here's a breakdown of what it does:

1. Initial Setup

s := []int{2, 3, 5, 7, 11, 13}
printSlice(s)

• A slice s is initialized with six integers: [2, 3, 5, 7, 11, 13].
• printSlice(s) is called, which prints the length, capacity, and elements of the slice:

  len=6 cap=6 [2 3 5 7 11 13]
  

2. Slice the slice to zero length

s = s[:0]
printSlice(s)

• The slice s is updated to have a length of 0 using s[:0]. This operation sets the slice length to zero while keeping the capacity unchanged.
• printSlice(s) prints:

  len=0 cap=6 []
  

3. Extend the slice length

s = s[:4]
printSlice(s)

• The slice s is extended back to length 4 using s[:4]. This restores the first four elements of the original slice because the capacity is still 6, allowing the slice to "grow back" up to this limit.
• printSlice(s) prints:

  len=4 cap=6 [2 3 5 7]
  

4. Drop the first two values

s = s[2:]
printSlice(s)

• The slice s is updated to drop the first two elements using s[2:]. This operation moves the slice's starting position two steps forward, reducing both its length and capacity relative to the original slice.
• printSlice(s) prints:

  len=2 cap=4 [5 7]
  

5. The printSlice Function

func printSlice(s []int) {
	fmt.Printf("len=%d cap=%d %v\n", len(s), cap(s), s)
}

• This helper function uses fmt.Printf to print the current length, capacity, and elements of a given slice.

Summary of Outputs

When you run the program, the output will be:

len=6 cap=6 [2 3 5 7 11 13]
len=0 cap=6 []
len=4 cap=6 [2 3 5 7]
len=2 cap=4 [5 7]

This code illustrates how Go slices are dynamic and can be resized and manipulated while sharing their underlying array.