Golang中的可变范围

Question

I am new in Go language and want to learn basic fundamental here below I paste example. the problem in this example is I cannot access number variable inside for loop. it shows this error

" number declared and not use "

. Please help me :(

package main
import(
    "fmt"
)

func main() {    
    samlestNumber()
}

func samlestNumber()  {
    x := []int{
        48,96,86,68,
        57,82,63,70,
        37,34,83,27,
        19,97, 9,17,
    }

    //x = append(x,6,7)
    var number int = x[0]
    for _,element := range x {

        if element < x[0] {
            number = element
        }    
        fmt.Println(" :::: ",element)    
    }
}

Answer 1

It is because you are only declaring and assigning values to number. You are never actually using it anywhere (i.e. referring to the value it holds in any way). In you code, you can safely remove number declaration and number = x[0] and it won't change the program behavior.

The correct implementation however would return the smallest number from the function:

package main
import(
    "fmt"
)

func main() {
    n := samlestNumber()
    fmt.Println("Smallest Number =", n)
}

func samlestNumber() int { // add a return type
    x := []int{
        48,96,86,68,
        57,82,63,70,
        37,34,83,27,
        19,97, 9,17,
    }

    //x = append(x,6,7)
    var number int = x[0]
    for _,element := range x {

        // always compare to smallest number. Even if you don't return
        // number anymore, you are still accessing the value held by
        // the number variable. So even making this change alone will
        // make the compiler error go away 
        if element < number {
            number = element
        }

        fmt.Println(" :::: ",element)
    }
    return number // return number
}