//golang slice and "for" question
//  when i use len(x) the output is not what i want. 
// because the len(x) change the size auto and the len(x) also change inside for 
// so the problem looks like when "for" condition check repeat not make const when first call for for with repating   
// answer with sfbanghm.yahoo.com

package main


import (
	"fmt"
)

func RmBack (arr []int) ([]int, int) {
	//var arrLen int
	//arrLen = len(arr)
	return arr[:len(arr)-1], arr[len(arr)-1]
	// for front 
	//return arr[1:], arr[0]
}

func main() {

	fmt.Println("Hello, playground")
	
	// slice a[starI: endi]  a(starti- endi] endindex not include
	x := []int {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
	px := &x
	xOrg := *px 
	fmt.Printf("xAdd: %p, pxAdd: %p\n", x, *px)
	fmt.Println("xAdd: ",x, "pxAdd: ", *px)
	y := x[4:8] //
	fmt.Println("x: [0 1 2 3 4 5 6 7 8 9 10]")
	fmt.Println("x: ",x, " y: ", y)
	//out=>x: [0 1 2 3 4 5 6 7 8 9 10]
	//out=>x:  [1 2 3 4 5 6 7 8 9 10]  y:  [5 6 7 8]
	fmt.Printf("xadd:%p, yadr:%p, x[4]adr:%p \n",x, y, &x[4])
	//out=>xadd:0xc000012050, yadr:0xc000012070, x[4]adr:0xc000012070 
	fmt.Println(x, len(x)) 
	//if useing len(x) and RmBack some how it dose not work as i except like len(x) 10
	var rmVal int
	
	for i := 0; i < 10 ; i++{
		x, rmVal = RmBack(x)
		fmt.Println("index: ",i,"x: ",x," rmVal: ",rmVal)
	}
	fmt.Println("xAdd: ",x, "pxAdd: ", *px," xorg: ",xOrg)
	
	// using len(u) at condtion of "for" and result is not what I want
	// at the "for" dose not make len(u) as constant at the call of "for" 
	
	u := []int {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
	for i := 0; i < len(u) ; i++{
		u, rmVal = RmBack(u)
		fmt.Println("index: ",i,"x: ",u," rmVal: ",rmVal)
	}
	
}

//Hello, playground
//xAdd: 0xc000138000, pxAdd: 0xc000138000
//xAdd:  [1 2 3 4 5 6 7 8 9 10] pxAdd:  [1 2 3 4 5 6 7 8 9 10]
//x: [0 1 2 3 4 5 6 7 8 9 10]
//x:  [1 2 3 4 5 6 7 8 9 10]  y:  [5 6 7 8]
//xadd:0xc000138000, yadr:0xc000138020, x[4]adr:0xc000138020 
//[1 2 3 4 5 6 7 8 9 10] 10
//index:  0 x:  [1 2 3 4 5 6 7 8 9]  rmVal:  10
//index:  1 x:  [1 2 3 4 5 6 7 8]  rmVal:  9
//index:  2 x:  [1 2 3 4 5 6 7]  rmVal:  8
//index:  3 x:  [1 2 3 4 5 6]  rmVal:  7
//index:  4 x:  [1 2 3 4 5]  rmVal:  6
//index:  5 x:  [1 2 3 4]  rmVal:  5
//index:  6 x:  [1 2 3]  rmVal:  4
//index:  7 x:  [1 2]  rmVal:  3
//index:  8 x:  [1]  rmVal:  2
//index:  9 x:  []  rmVal:  1
//xAdd:  [] pxAdd:  []  xorg:  [1 2 3 4 5 6 7 8 9 10]
//index:  0 x:  [1 2 3 4 5 6 7 8 9]  rmVal:  10
//index:  1 x:  [1 2 3 4 5 6 7 8]  rmVal:  9
//index:  2 x:  [1 2 3 4 5 6 7]  rmVal:  8
//index:  3 x:  [1 2 3 4 5 6]  rmVal:  7
//index:  4 x:  [1 2 3 4 5]  rmVal:  6

//Program exited.