Home Software Engineering The way to carry out Perform Iteration in Golang

## The problem#

The aim of this problem is to write down a higher-order perform returning a brand new perform that iterates on a specified perform a given variety of instances. This new perform takes in an argument as a seed to start out the computation.

For example, think about the perform `getDouble`. When run twice on worth `3`, yields `12` as proven under.

``````getDouble(3) => 6
getDouble(6) => 12
``````

Allow us to identify the brand new perform `createIterator` and we should always have the ability to receive the identical end result utilizing `createIterator` as proven under:

``````var doubleIterator = createIterator(getDouble, 2); // Runs *getDouble* twice
doubleIterator(3) => 12
``````

For the sake of simplicity, all perform inputs to `createIterator` would perform returning a small quantity and the variety of iterations would all the time be integers.

Choice 1:

``````bundle resolution
func CreateIterator(fn func(int) int,n int) func(int) int {
return func (i int) int {
for j := 0; j < n; j++ { i = fn(i) }
return i
}
}
``````

Choice 2:

``````bundle resolution
func CreateIterator(fn func(int) int,n int) func(int) int {
if n == 0 {
return func(x int) int { return x } // id
} else {
return func(x int) int { return CreateIterator(fn, n-1)(fn(x)) }
}
}
``````

Choice 3:

``````bundle resolution
func CreateIterator(fn func(int) int,n int) func(int) int {
if n < 1 {
return nil
}
var retFunc = func(r int) int {
for i := n ; i>0 ; i-- {
r = fn(r)
}
return r
}
return retFunc
}
``````

## Check instances to validate our resolution#

``````bundle solution_test
import (
. "github.com/onsi/ginkgo"
. "github.com/onsi/gomega"
)
var _ = Describe("Iterator for 'getDouble' perform",func() {
var getDouble = func(n int) int {return 2*n}
It("Operating the iterator as soon as",func() {
doubleIterator := CreateIterator(getDouble,1)
Count on(doubleIterator(3)).To(Equal(6))
Count on(doubleIterator(5)).To(Equal(10))
})
It("Operating the iterator twice",func() {