package main

import "fmt"

func plus(a int, b int) int {
	return a + b
}

func plusPlus(a, b, c int) int {
	return a + b + c
}

// multiple return values
func vals() (int, int) {
	return 3, 7
}

// variadic functions
func sum(nums ...int) {
	fmt.Println(nums, " ")
	total := 0

	for _, num := range nums {
		total += num
	}
	fmt.Println(total)
}

// Closures
func intSeq() func() int {
	i := 0
	return func() int {
		i++
		return i
	}
}

// Recursion
func fact(n int) int {
	print(n)
	print("Recursion")
	if n == 0 {
		return 1
	}
	return n * fact(n-1)
}

func main() {

	// functions
	res := plus(1, 2)
	fmt.Println("1 + 2 =", res)

	res = plusPlus(1, 2, 3)
	fmt.Println("1 + 2 + 3 =", res)

	// multiple return values
	a, b := vals()

	fmt.Println(a)
	fmt.Println(b)

	_, c := vals()
	fmt.Println(c)

	// variadic
	sum(1, 2, 3, 4, 5, 6)
	sum(2, 10, 40)
	sum([]int{5, 10, 10}...)

	// Closures
	nextInt := intSeq()

	fmt.Println(nextInt())
	fmt.Println(nextInt())
	fmt.Println(nextInt())

	newInts := intSeq()
	fmt.Println(newInts())

	// Recursion
	// Classic recursion example
	fmt.Println(fact(7))
}