模式特点：通过吧不变的行为搬到父类，去除子类中的重复代码。
程序实例：考试时使用同一种考卷（父类），不同学生上交自己填写的试卷（子类方法的实现）

package main

import (
	"fmt"
)

type TestPaper struct {
	child interface{}
}

func (t *TestPaper) testQuestion1() {
	fmt.Println("杨过得到，后来给了郭靖，练成倚天剑、屠龙刀的玄铁可能是[] a.球磨铸铁 b.马口铁 c.高速合金钥 d.碳素纤维")
	fmt.Println("答案：", t.child.(Answers).answer1())
}

func (t *TestPaper) testQuestion2() {
	fmt.Println("杨过、程英、陆无双铲除了情花.造成[] a.使这种植物不再害人 b.使一种珍稀物种灭绝 c.破坏了那个生物圈的生态平衡 d.造成该地区沙漠化")
	fmt.Println("答案：", t.child.(Answers).answer2())
}

func (t *TestPaper) testQuestion3() {
	fmt.Println("蓝凤凰致使华山师徒、桃谷六仙呕吐不止，如果你是大夫，会给他们开什么药[] a.阿司匹林 b.牛黄解毒片 c.氟呱酸 d.让他们喝大量的生牛奶 e.以上全不对")
	fmt.Println("答案：", t.child.(Answers).answer3())
}

type Answers interface {
	answer1() string
	answer2() string
	answer3() string
}

type TestPaperA struct {
	TestPaper
}

func NewTestPaperA() *TestPaper {
	paper := &TestPaper{}
	var answer Answers = &TestPaperA{}
	paper.child = answer

	return paper

}

func (t *TestPaperA) answer1() string {
	return "b"
}

func (t *TestPaperA) answer2() string {
	return "c"
}

func (t *TestPaperA) answer3() string {
	return "a"
}

type TestPaperB struct {
	TestPaper
}

func NewTestPaperB() *TestPaper {
	paper := &TestPaper{}
	var answer Answers = &TestPaperB{}
	paper.child = answer

	return paper

}
func (t *TestPaperB) answer1() string {
	return "c"
}

func (t *TestPaperB) answer2() string {
	return "a"
}

func (t *TestPaperB) answer3() string {
	return "a"
}

func main() {
	studentA := NewTestPaperA()
	studentA.testQuestion1()
	studentA.testQuestion2()
	studentA.testQuestion3()

	studentB := NewTestPaperB()
	studentB.testQuestion1()
	studentB.testQuestion2()
	studentB.testQuestion3()
}

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