添加06.2.md和相关的例子与问题解答

eBook/examples/chapter_6/simple_function.go

@@ -0,0 +1,15 @@
+package main
+
+import "fmt"
+
+func main() {
+    fmt.Printf("Multiply 2 * 5 * 6 = %d\n", MultiPly3Nums(2, 5, 6))
+    // var i1 int = MultiPly3Nums(2, 5, 6)
+    // fmt.Printf("MultiPly 2 * 5 * 6 = %d\n", i1)
+}
+
+func MultiPly3Nums(a int, b int, c int) int {
+    // var product int = a * b * c
+        // return product
+        return a * b * c
+}