// Simple stupid Fibonacci microbenchmark.  See dumbfib.S and concfib.go.
// On my old laptop:
// $ time ./fib 40
// 165580141
//
// real	0m2.607s
// user	0m2.596s
// sys	0m0.008s
//
// That used to be (/ 2.607 .910) = 2.86 times slower than
// GCC-compiled C.  It amounts to (/ 165580141.0 2.607) = 64 million
// leaf calls per second.

// GCC has improved to the point where that’s no longer a useful
// comparison.  On this Celeron N4120 with argument 39 I get
// 102334155, corresponding to 40 in dumbfib.S, in 824–826
// milliseconds, about 21% slower than dumbfib.S.

package main

import (
	"fmt"
	"os"
	"strconv"
)

func fib(n int) int {
	if n < 2 {
		return 1
	} else {
		return fib(n-1) + fib(n-2)
	}
}

func main() {
	n, err := strconv.Atoi(os.Args[1])
	if err != nil {
		panic("whoa")
	}
	fmt.Println(fib(n))
}