在此篇中，将要练习策略模式。例子仍然是采用菜鸟教程（http://www.runoob.com/design-pattern/strategy-pattern.html）

package main

import "fmt"

func main() {
   con := new(Content)
   con.Strategy = OperationAdd{}
   v := con.executeStrategy(1,2)
   fmt.Println(v)
   con.Strategy = OperationMultiply{}
   v1 := con.executeStrategy(1,2)
   fmt.Println(v1)
}

type Content struct {
   Strategy Strategy
}

func (c Content) executeStrategy(num1 int,num2 int) int {
   return c.Strategy.doOperation(num1, num2)
}


type Strategy interface {
   doOperation(num1 int,num2 int) int
}

//加计算
type OperationAdd struct {
   
}

func (add OperationAdd ) doOperation(num1 int,num2 int) int {
   return num1 + num2
}

//乘计算
type OperationMultiply struct {

}

func (add OperationMultiply ) doOperation(num1 int,num2 int) int {
   return num1 * num2
}