func main() {
a := []string{}
a = append(a, "hello")
a = append(a, ", ")
a = append(a, "world")
fmt.Println(a)

for i := 0; i < len(a); i++ {
	fmt.Println(a[i])
}

for _, aa := range a {
	aa += "@"
	fmt.Println(aa)
}
for i :=0;i<len(a);i++ {
	a[i] += "@"
	fmt.Println(a[i])
}
fmt.Println(a)

}
打印99 乘法表

func main()  {
	for i :=1;i<=9;i++{
		for j:=1;j<=i;j++{
			fmt.Printf("%d*%d=%d  ",i,j,i*j)
		}
		fmt.Println()
	}
}