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/*
SYNOPSIS:
With GCC >= 4.6:
# gccgo gcd.go -o gcd-go
# ./gcd-go 11 22 33 44 121
With Google Go (http://golang.org/):
# go run gcd.go 11 22 33 44 121
# or, if you want to play with the binary
# go build -o gcd-go gcd.go
# ./gcd-go 11 22 33 44 121
GCC makes dynamically linked binary,
but Google Go - statically linked
*/
package main
// Both Google Go and GCC issue an error "imported and not used",
// if imported and not used :-)
import "fmt"
import "flag"
import "strconv"
func gcd2(a, b uint64) uint64 {
if b == 0 {
return a
}
/* 6g issues an error "function ends without a return statement",
if we use if ... {... return} else {... return}.
But GCC doesn't.
*/
return gcd2(b, a%b)
}
func gcdn(ns []uint64) uint64 {
var r uint64 // zero by default
for i := range ns {
r = gcd2(r, ns[i])
}
return r
}
func main() {
flag.Parse() // without this 6g will give flag.NArg() = 0 next (WTF?)
n := flag.NArg()
if n > 0 {
ns := make([]uint64, n) // We have garbage collector!
// Or: for i := range ns, since range of ns is equal to flag.NArg()
for i := 0; i < n; i++ {
// Drop the second return value (error code):
ns[i], _ = strconv.ParseUint(flag.Arg(i), 0, 64)
}
g := gcdn(ns)
fmt.Printf("%v\n", g)
}
}
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