//接口中可以组合其它接口，这种方式等效于在接口中添加其它接口的方法 
type Reader interface { 
    read() 
} 
type Writer interface { 
    write() 
} 
 
//定义上述两个接口的实现类 
type MyReadWrite struct{} 
 
func (mrw *MyReadWrite) read() { 
    fmt.Println("MyReadWrite...read") 
} 
 
func (mrw *MyReadWrite) write() { 
    fmt.Println("MyReadWrite...write") 
} 
 
//定义一个接口，组合了上述两个接口 
type ReadWriter interface { 
    Reader 
    Writer 
} 
 
//上述接口等价于： 
type ReadWriterV2 interface { 
    read() 
    write() 
} 
 
//ReadWriter和ReadWriterV2两个接口是等效的，因此可以相互赋值 
func interfaceTest0104() { 
    mrw := &MyReadWrite{} 
    //mrw对象实现了read()方法和write()方法，因此可以赋值给ReadWriter和ReadWriterV2 
    var rw1 ReadWriter = mrw 
    rw1.read() 
    rw1.write() 
 
    fmt.Println("------") 
    var rw2 ReadWriterV2 = mrw 
    rw2.read() 
    rw2.write() 
 
    //同时，ReadWriter和ReadWriterV2两个接口对象可以相互赋值 
    rw1 = rw2 
    rw2 = rw1 
}