added an interface, moved fibonacci numbrers to own file, and added a counter iterator (4bc2fd32) · Commits · bsmrgo / playground

iterators/counter.go

0 → 100644

+31 −0

Original line number	Diff line number	Diff line
		package iterators

		import (
		"math/big"
		)

		// Counter ...
		type Counter struct {
		count *big.Int
		}

		// NewCounterIterator ...
		func NewCounterIterator(start big.Int) Counter {
		return &Counter{
		count: start,
		}
		}

		// Value ...
		func (c Counter) Value() big.Int {
		return c.count
		}

		var (
		one = big.NewInt(1)
		)

		// Next ...
		func (c *Counter) Next() {
		c.count.Add(c.count, one)
		}

0 → 100644

+31 −0

Original line number	Diff line number	Diff line
		package iterators

		import (
		"math/big"
		)

		// https://en.wikipedia.org/wiki/Fibonacci_number

		// FibonacciNumber ...
		type FibonacciNumber struct {
		current *big.Int
		next *big.Int
		}

		// NewFibonacciNumberIterator ...
		func NewFibonacciNumberIterator() *FibonacciNumber {
		return &FibonacciNumber{
		current: big.NewInt(0),
		next: big.NewInt(1),
		}
		}

		// Value ...
		func (fn FibonacciNumber) Value() big.Int {
		return fn.current
		}

		// Next ...
		func (fn *FibonacciNumber) Next() {
		fn.current, fn.next = fn.next, fn.current.Add(fn.next, fn.current)
		}

+8 −26

Original line number	Diff line number	Diff line
		package iterators

		import "math/big"

		// https://en.wikipedia.org/wiki/Fibonacci_number

		// FibonacciNumber ...
		type FibonacciNumber struct {
		current *big.Int
		next *big.Int
		}

		// NewFibonacciNumberIterator ...
		func NewFibonacciNumberIterator() *FibonacciNumber {
		return &FibonacciNumber{
		current: big.NewInt(0),
		next: big.NewInt(1),
		}
		}

		// Value ...
		func (fn FibonacciNumber) Value() big.Int {
		return fn.current
		}

		// Next ...
		func (fn *FibonacciNumber) Next() {
		fn.current, fn.next = fn.next, fn.current.Add(fn.next, fn.current)
		import (
		"math/big"
		)

		// BigIntIterator is an iterator for big.Ints.
		type BigIntIterator interface {
		Next()
		Value() *big.Int
		}

+16 −3

Original line number	Diff line number	Diff line
		package iterators

		import (
		"math/big"
		"testing"
		)

		func TestIterators1(t *testing.T) {
		fn := NewFibonacciNumberIterator()
		var iter BigIntIterator = NewFibonacciNumberIterator()
		for i := 0; i < 20; i++ {
		t.Logf("F(%d): %s", i, fn.Value())
		fn.Next()
		t.Logf("F(%d): %s", i, iter.Value())
		iter.Next()
		}
		}

		func TestIterators2(t *testing.T) {
		for i, iter := range []BigIntIterator{
		NewCounterIterator(big.NewInt(10)),
		NewFibonacciNumberIterator(),
		} {
		for j := 0; j < 20; j++ {
		t.Logf("F%d(%d): %s", i, j, iter.Value())
		iter.Next()
		}
		}
		}