count_from_1_to_1000000000.go

package main

import (
	"fmt"
	"time"
)

//for this question: http://www.v2ex.com/t/139818#reply98
func main() {
	var sum, i int64
	start := time.Now().UnixNano()
	for i = 0; i <= 1000000000; i++ {
		sum += i
	}

	fmt.Println(sum, float64(time.Now().UnixNano()-start)/1000000000.00)
}

//result:500000000500000000 0.8236045