What will the code with slices and passing to a function output? How does passing a slice to a function work?

In Go, slices are passed to functions by value, but only the slice structure (pointer to the array, length, capacity) is copied, not the underlying array itself. This means that changes to the elements of the slice inside the function are reflected in the original array.

Example:

func modify(slice []int) {
    slice[0] = 100
    slice = append(slice, 200) // modifies the local slice, the original remains unchanged
}

func main() {
    s := []int{1, 2, 3}
    modify(s)
    fmt.Println(s) // Will output: [100 2 3]
}

Explanation:

• slice[0] = 100 changes the element in the original array.
• append may create a new array if capacity is insufficient, but this does not affect the original slice in main.

Thus, passing a slice allows modifying the contents of the array, but not the slice structure itself (such as length) outside the function.