Explain the difference between LIFO and FIFO using the example of a stack and a queue.

LIFO (Last In, First Out) and FIFO (First In, First Out) are two methods of organizing data.

• LIFO — last arrived, first out. Example: stack. The most recently added element is retrieved first.
• FIFO — first arrived, first out. Example: queue. Elements are retrieved in the order they were added.

Example in Go:

package main

import "fmt"

func main() {
    // Stack (LIFO)
    stack := []int{}
    stack = append(stack, 1) // push
    stack = append(stack, 2)
    fmt.Println("Stack:", stack)
    top := stack[len(stack)-1]
    stack = stack[:len(stack)-1] // pop
    fmt.Println("Popped element (LIFO):", top)

    // Queue (FIFO)
    queue := []int{1, 2, 3}
    fmt.Println("Queue:", queue)
    first := queue[0]
    queue = queue[1:] // dequeue
    fmt.Println("Dequeued element (FIFO):", first)
}

In this example, the stack retrieves the last added element, while the queue retrieves the first.