Goroutine inside for loop takes only the last value of slice

Can anyone explain this behavior to me?

package main
import (
	"fmt"
	"time"
)
func main() {
	a := []int64{1, 2, 3, 4, 5}
	for _,v := range a {
		go func(){
			fmt.Println("value is ", v)
		}()
			
	}
	time.Sleep(2*time.Second)
	
}

this code prints the following output.

value is  5
value is  5
value is  5
value is  5
value is  5

Why does the goroutine take only the last value in the slice when no input parameter is passed?

Edit: I just want to know how the program is executing. Every goroutine is having the same value, but why is it always the last value? (Doubt: does goroutine execute only after looping through all the elements in slice? )

Because each of the goroutines hold the same variable v.
If you want to take diffrent value of the silce, do like this:

func main() {
a := []int64{1, 2, 3, 4, 5}
for _,v := range a {
	v2 := v
	go func(){
		fmt.Println("value is ", v2)
	}()
}
time.Sleep(2*time.Second)

}

Output is:

value is  1
value is  2
value is  3
value is  4
value is  5