Add CompactToBig example.

README.md

@@ -82,6 +82,12 @@ is by no means exhaustive:
   attempts to insert a duplicate genesis block to illustrate how an invalid
   block is handled.
 
+* [CompactToBig Example]
+  (http://godoc.org/github.com/conformal/btcchain#example-CompactToBig)  
+  Demonstrates how to convert the "bits" in a block header which represent the
+  target difficulty to a big integer and display it using the typical hex
+  notation.
+
 ## TODO
 
 - Increase test coverage

doc.go

@@ -61,14 +61,6 @@ is by no means exhaustive:
    coins
  - Insert the block into the block database
 
-Examples
-
- - ProcessBlock Example
-   Demonstrates how to create a new chain instance and use ProcessBlock to
-   attempt to attempt add a block to the chain.  This example intentionally
-   attempts to insert a duplicate genesis block to illustrate how an invalid
-   block is handled.
-
 Errors
 
 Errors returned by this package are either the raw errors provided by underlying

example_test.go

@@ -57,3 +57,18 @@ func ExampleBlockChain_ProcessBlock() {
 	// Output:
 	// Failed to process block: already have block 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f
 }
+
+// This example demonstrates how to convert the "bits" in a block header which
+// represent the target difficulty to a big integer and display it using the
+// typical hex notation..
+func ExampleCompactToBig() {
+	// Convert the bits from block 300000 in the main block chain.
+	bits := uint32(419465580)
+	targetDifficulty := btcchain.CompactToBig(bits)
+
+	// Display it in hex.
+	fmt.Printf("%064x\n", targetDifficulty.Bytes())
+
+	// Output:
+	// 0000000000000000896c00000000000000000000000000000000000000000000
+}