[GO] slice

package main

import "fmt"

func test1() {
    fmt.Println("test1 ------------------")
    s := []int{2, 3, 5, 7, 11, 13}
    printSlice("s", s)
    printSlice("s[1:4]", s[1:4])
    printSlice("s[:3]", s[:3])
    printSlice("s[4:]", s[4:])

    a := s[2:5]
    printSlice("a", a)

    a[0] = 100
    printSlice("a", a)
    printSlice("s", s)
}

func test2() {
    fmt.Println("test2 ------------------")
    var arr [10]int
    for i := 0; i < 10; i++ {
        arr[i] = i
    }
    arrS := arr[:]
    fmt.Println(arr)
    printSlice("arrS", arrS)

    arrS[0] = 100
    fmt.Println(arr)
    printSlice("arrS", arrS)
}

func test3() {
    fmt.Println("test3 ------------------")
    a := make([]int, 5)
    printSlice("a", a)
    //b := make([]int, 0, 5)
    b := make([]int, 5, 5) //change len to 5, you will know why.
    printSlice("b", b)
    c := b[:2]
    printSlice("c", c)
    d := c[2:5]
    printSlice("d", d)

    c[0] = 200
    fmt.Println("-------------")
    printSlice("a", a)
    printSlice("b", b)
    printSlice("c", c)
    printSlice("d", d)

    d[0] = 100
    fmt.Println("-------------")
    printSlice("a", a)
    printSlice("b", b)
    printSlice("c", c)
    printSlice("d", d)
}

func printSlice(s string, x []int) {
    fmt.Printf("%s len=%d cap=%d %v\n",
        s, len(x), cap(x), x)
}

func main() {
    test1()
    test2()
    test3()
}