Extract Block and Blockchain into separate files

block.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"crypto/sha256"
+	"log"
+	"strconv"
+	"time"
+)
+
+// Block keeps block headers
+type Block struct {
+	Timestamp int64
+	Data      []byte
+	PrevBlock []byte
+	hash      []byte
+}
+
+// SetHash calculates and sets block hash
+func (b *Block) SetHash() {
+	h := sha256.New()
+	timestamp := []byte(strconv.FormatInt(b.Timestamp, 10))
+	var data []byte
+	data = append(data, b.PrevBlock...)
+	data = append(data, b.Data...)
+	data = append(data, timestamp...)
+
+	_, err := h.Write(data)
+	if err != nil {
+		log.Panic(err)
+	}
+	b.hash = h.Sum(nil)
+}
+
+// NewBlock creates and returns Block
+func NewBlock(data string, prevBlock []byte) *Block {
+	block := &Block{time.Now().Unix(), []byte(data), prevBlock, []byte("")}
+	block.SetHash()
+	return block
+}
+
+// NewGenesisBlock creates and returns genesis Block
+func NewGenesisBlock() *Block {
+	return NewBlock("Genesis Block", []byte("0"))
+}

blockchain.go

@@ -0,0 +1,21 @@
+package main
+
+import "time"
+
+// Blockchain keeps a sequence of Blocks
+type Blockchain struct {
+	blocks []*Block
+}
+
+// AddBlock saves provided data as a block in the blockchain
+func (bc *Blockchain) AddBlock(data string) {
+	prevBlock := bc.blocks[len(bc.blocks)-1]
+	newBlock := &Block{time.Now().Unix(), []byte(data), prevBlock.hash, []byte("")}
+	newBlock.SetHash()
+	bc.blocks = append(bc.blocks, newBlock)
+}
+
+// NewBlockchain creates a new Blockchain with genesis Block
+func NewBlockchain() *Blockchain {
+	return &Blockchain{[]*Block{NewGenesisBlock()}}
+}

main.go

@@ -1,67 +1,9 @@
 package main
 
 import (
-	"crypto/sha256"
 	"fmt"
-	"log"
-	"strconv"
-	"time"
 )
 
-// Block keeps block headers
-type Block struct {
-	Timestamp int64
-	Data      []byte
-	PrevBlock []byte
-	hash      []byte
-}
-
-// SetHash calculates and sets block hash
-func (b *Block) SetHash() {
-	h := sha256.New()
-	timestamp := []byte(strconv.FormatInt(b.Timestamp, 10))
-	var data []byte
-	data = append(data, b.PrevBlock...)
-	data = append(data, b.Data...)
-	data = append(data, timestamp...)
-
-	_, err := h.Write(data)
-	if err != nil {
-		log.Panic(err)
-	}
-	b.hash = h.Sum(nil)
-}
-
-// NewBlock creates and returns Block
-func NewBlock(data string, prevBlock []byte) *Block {
-	block := &Block{time.Now().Unix(), []byte(data), prevBlock, []byte("")}
-	block.SetHash()
-	return block
-}
-
-// NewGenesisBlock creates and returns genesis Block
-func NewGenesisBlock() *Block {
-	return NewBlock("Genesis Block", []byte("0"))
-}
-
-// Blockchain keeps a sequence of Blocks
-type Blockchain struct {
-	blocks []*Block
-}
-
-// AddBlock saves provided data as a block in the blockchain
-func (bc *Blockchain) AddBlock(data string) {
-	prevBlock := bc.blocks[len(bc.blocks)-1]
-	newBlock := &Block{time.Now().Unix(), []byte(data), prevBlock.hash, []byte("")}
-	newBlock.SetHash()
-	bc.blocks = append(bc.blocks, newBlock)
-}
-
-// NewBlockchain creates a new Blockchain with genesis Block
-func NewBlockchain() *Blockchain {
-	return &Blockchain{[]*Block{NewGenesisBlock()}}
-}
-
 func main() {
 	bc := NewBlockchain()