简单工厂模式--Golang版本

目录结构：
  | -- calculater-simpleFactory
    | -- main.go
    | -- Calculater
    |   | -- Calculater.go

• main.go

package main

import (
    "calculater-simpleFactory/Calculater"
    "fmt"
)

func main() {

    numbers := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
    opreate := Calculater.NewCalculate("+")
    sum, _ := opreate.Opreation(numbers)
    fmt.Println("sum = ", sum)

    opreate2 := Calculater.NewCalculate("-")
    res, _ := opreate2.Opreation(numbers)
    fmt.Println("res = ", res)

}

Calculater.go

/*
 * @Description:
 * @Author: huacong
 * @Date: 2020-03-22 17:33:43
 * @LastEditTime: 2020-03-22 18:26:28
 * @LastEditors: huacong
 */
package Calculater

import (
    "errors"
    "fmt"
)

//计算器接口
type Calculater interface {
    Opreation(numbers []int) (int, error)
}

func NewCalculate(opreate string) Calculater {
    var calculater Calculater
    switch opreate {
    case "+":
        calculater = new(CalculateAdd)
    default:
        calculater = new(CalculateSubtraction)
    }
    return calculater
}

type CalculateAdd struct{}

func (*CalculateAdd) Opreation(numbers []int) (int, error) {
    if len(numbers) < 2 {
        return 0, errors.New("运算数字不能少于2个")
    }

    sum := 0
    for _, v := range numbers {
        sum += v
    }
    return sum, nil
}

type CalculateSubtraction struct{}

func (*CalculateSubtraction) Opreation(numbers []int) (int, error) {
    if len(numbers) < 2 {
        return 0, errors.New("运算数字不能少于2个")
    }

    sum := numbers[0]
    for i := 1; i < len(numbers); i++ {
        fmt.Println(sum - numbers[i])
        sum -= numbers[i]
    }
    return sum, nil
}