added float

Author: vtopc

float/README.md

@@ -0,0 +1,13 @@
+# Comparing float implementations and JSON serialization
+
+## input
+
+`1234567890123456.87`
+
+## output
+
+```
+float64: {"price":1234567890123456.8}
+big.Float: {"price":"1.2345678901234568e+15"}
+shopspring/decimal.Decimal: {"price":"1234567890123456.87"}
+```

float/big_float.go

@@ -0,0 +1,21 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"math/big"
+)
+
+type BigFloat struct {
+	Price *big.Float `json:"price"`
+}
+
+func bigFloat() {
+	v := BigFloat{
+		Price: big.NewFloat(1234567890123456.87),
+	}
+
+	b, _ := json.Marshal(v)
+
+	fmt.Println("big.Float:", string(b))
+}

float/float.go

@@ -0,0 +1,20 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+type Float struct {
+	Price float64 `json:"price"`
+}
+
+func float() {
+	v := Float{
+		Price: 1234567890123456.87,
+	}
+
+	b, _ := json.Marshal(v)
+
+	fmt.Println("float64:", string(b))
+}

float/go.mod

@@ -0,0 +1,5 @@
+module float
+
+go 1.16
+
+require github.com/shopspring/decimal v1.2.0 // indirect

float/go.sum

@@ -0,0 +1,2 @@
+github.com/shopspring/decimal v1.2.0 h1:abSATXmQEYyShuxI4/vyW3tV1MrKAJzCZ/0zLUXYbsQ=
+github.com/shopspring/decimal v1.2.0/go.mod h1:DKyhrW/HYNuLGql+MJL6WCR6knT2jwCFRcu2hWCYk4o=

float/main.go

@@ -0,0 +1,7 @@
+package main
+
+func main() {
+	float()
+	bigFloat()
+	shopspringDecimal()
+}

float/shopspring_decimal.go

@@ -0,0 +1,24 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"github.com/shopspring/decimal"
+)
+
+type ShopspringDecimal struct {
+	Price decimal.Decimal `json:"price"`
+}
+
+func shopspringDecimal() {
+	p, _ := decimal.NewFromString("1234567890123456.87")
+
+	v := ShopspringDecimal{
+		Price: p,
+	}
+
+	b, _ := json.Marshal(v)
+
+	fmt.Println("shopspring/decimal.Decimal:", string(b))
+}