diff --git a/README.md b/README.md
index 10592d0..0a68248 100644
--- a/README.md
+++ b/README.md
@@ -7,6 +7,7 @@ Git is a version control system that allows you to keep track of the files that
 A collection of files under Git's control is called a repository.
 
 There are several ways you can work with the code:
+*   You can edit and run the code on [Codiva online java IDE](https://www.codiva.io/tutorials/thinkjavacode).
 
 *   You can create a copy of this repository on GitHub by pressing the "Fork" button in the upper right.
 If you don't already have a GitHub account, you'll need to create one.
diff --git a/ch05/Logarithm.java b/ch05/Logarithm.java
index bc21157..5c5986a 100644
--- a/ch05/Logarithm.java
+++ b/ch05/Logarithm.java
@@ -6,11 +6,13 @@ public static void main(String[] args) {
         System.out.println("printLogarithm");
         printLogarithm(3.0);
 
+        Scanner in = new Scanner(System.in);
+
         System.out.println("scandouble");
-        scanDouble();
+        scanDouble(in);
 
         System.out.println("scandouble2");
-        scanDouble2();
+        scanDouble2(in);
     }
 
     public static void printLogarithm(double x) {
@@ -22,15 +24,13 @@ public static void printLogarithm(double x) {
         System.out.println("The log of x is " + result);
     }
 
-    public static void scanDouble() {
-        Scanner in = new Scanner(System.in);
+    public static void scanDouble(Scanner in) {
         System.out.print("Enter a number: ");
         double x = in.nextDouble();
         printLogarithm(x);
     }
 
-    public static void scanDouble2() {
-        Scanner in = new Scanner(System.in);
+    public static void scanDouble2(Scanner in) {
         System.out.print("Enter a number: ");
         if (!in.hasNextDouble()) {
             String word = in.next();
diff --git a/ch07/Tables.java b/ch07/Tables.java
index 44e9e62..3e33905 100644
--- a/ch07/Tables.java
+++ b/ch07/Tables.java
@@ -6,7 +6,7 @@ public class Tables {
     public static void example() {
         int i = 1;
         while (i < 10) {
-            double x = (double) i;
+            double x = i;
             System.out.println(x + "   " + Math.log(x));
             i = i + 1;
         }
@@ -15,7 +15,7 @@ public static void example() {
     public static void example2() {
         int i = 1;
         while (i < 10) {
-            double x = (double) i;
+            double x = i;
             System.out.println(x + "   " + Math.log(x) / Math.log(2));
             i = i + 1;
         }
@@ -25,7 +25,7 @@ public static void example3() {
         final double LOG2 = Math.log(2);
         int i = 1;
         while (i < 100) {
-            double x = (double) i;
+            double x = i;
             System.out.println(x + "   " + Math.log(x) / LOG2);
             i = i * 2;
         }