go学习

方法package mainimport (    "fmt"    "math")type Rect struct {    width, heigtht float32}type Cir struct {    r float32}func (r Rect) Cal() float32 {    return r.heigtht * r.width}func (r Cir) Cal() float32 {    return r.r * r.r * math.Pi}func main() {    a := Rect{2, 3}    fmt.Print(a.Cal())    b := Cir{4}    fmt.Print(b.Cal())}