feat: add factory

.gitignore

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+.idea/
+.DS_Store

README.md

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+## 说明
+
+《大话设计模式》 代码记录

factory/cash_factory.go

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+package factory
+
+func CreateCashAccept(t int) Casher {
+	var cash Casher
+	switch t {
+	case 1: //正常
+		cash = new(CashNormal)
+	case 2: //8折
+		cash = &CashRebate{moneyRebate: 0.8}
+	case 3: //满300减50
+		cash = &CashReturn{moneyCondition: 300, moneyReturn: 50}
+	default:
+	}
+	return cash
+}

factory/cash_normal.go

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+package factory
+
+type CashNormal struct{}
+
+func (c *CashNormal) AcceptCash(money float64) float64 {
+	return money
+}

factory/cash_rebate.go

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+package factory
+
+// CashRebate
+// @Description: 打折收费
+type CashRebate struct {
+	moneyRebate float64
+}
+
+func (c *CashRebate) AcceptCash(money float64) float64 {
+	return money * c.moneyRebate
+}

factory/cash_return.go

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+package factory
+
+import "math"
+
+// CashReturn
+// @Description: 返利收费
+type CashReturn struct {
+	moneyCondition float64
+	moneyReturn    float64
+}
+
+func (c *CashReturn) AcceptCash(money float64) float64 {
+	ret := money
+	if money >= c.moneyCondition {
+		ret = money - math.Floor(money/c.moneyCondition)*c.moneyReturn
+	}
+	return ret
+}

factory/cash_test.go

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+package factory
+
+import "testing"
+
+func TestCashNormal_AcceptCash(t *testing.T) {
+	accept := CreateCashAccept(1)
+	if accept == nil {
+		t.Error("testing failed")
+	}
+	money := 300.0
+	ret := accept.AcceptCash(money)
+	t.Log("\t应付: ", money)
+	t.Log("\t实付: ", ret)
+}
+
+func TestCashRebate_AcceptCash(t *testing.T) {
+	accept := CreateCashAccept(2)
+	if accept == nil {
+		t.Error("testing failed")
+	}
+	money := 300.0
+	ret := accept.AcceptCash(money)
+	t.Log("\t应付: ", money)
+	t.Log("\t实付: ", ret)
+}
+
+func TestCashReturn_AcceptCash(t *testing.T) {
+	accept := CreateCashAccept(3)
+	if accept == nil {
+		t.Error("testing failed")
+	}
+	money := 300.0
+	ret := accept.AcceptCash(money)
+	t.Log("\t应付: ", money)
+	t.Log("\t实付: ", ret)
+}
+
+func TestCash(t *testing.T) {
+	accept := CreateCashAccept(4)
+	if accept == nil {
+		t.Fatal("testing failed")
+	}
+	money := 300.0
+	ret := accept.AcceptCash(money)
+	t.Log("\t应付: ", money)
+	t.Log("\t实付: ", ret)
+}

factory/casher.go

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+package factory
+
+type Casher interface {
+	AcceptCash(money float64) float64
+}

go.mod

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+module designpatterns
+
+go 1.19