ring package in Golang

Go language provides a ring package that implements operations on circular lists. To access the functions of the ring package you need to import the ring package in your program with the help of the import keyword.

Method	Description
func New	This method is used to create a ring of the n elements.
func (*Ring) Do	This method is used to call function f on each element of the ring in forward order.
func (*Ring) Len	This method is used to computes the number of elements in ring r.
func (*Ring) Link	This method is used to connects ring r with ring s such that r.
func (*Ring) Move	This method is used to moves n % r.Len() elements backward (n < 0) or forward (n >= 0) in the ring and returns that ring element.
func (*Ring) Next	This method is used to returns the next ring element.
func (*Ring) Prev	This method is used to returns the previous ring element.
func (*Ring) Unlink	This method is used to removes n % r.Len() elements from the ring given r, starting at r.Next().

Example 1:

// Golang program to illustrate
// the ring.Len() function
package main

import (
    "container/ring"
    "fmt"
)
// Main function
func main() {

    // Creating a new ring of size 5
    r_ring := ring.New(5)

    // Print out its length
    fmt.Println(r_ring.Len())

}

Output:

5

Example 2:

// Golang program to illustrate
// the ring.Link() function
package main

import (
    "container/ring"
    "fmt"
)

// Main function
func main() {

    // Create two rings, r1 and r2, of size 3
    r1 := ring.New(3)
    r2 := ring.New(3)

    // Get the length of the ring
    lr := r1.Len()
    ls := r2.Len()

    // Initialize r1 with "GFG"
    for i := 0; i < lr; i++ {
        r1.Value = "GFG"
        r1 = r1.Next()
    }

    // Initialize r2 with "GOLang"
    for j := 0; j < ls; j++ {
        r2.Value = "GoLang"
        r2 = r2.Next()
    }

    // Link ring r1 and ring r2
    rs := r1.Link(r2)

    // Iterate through the combined
    // ring and print its contents
    rs.Do(func(p interface{}) {
        fmt.Println(p.(string))
    })
}

Output:

GFG
GFG
GFG
GoLang
GoLang
GoLang