ch07 revisions

Author: ChrisMayfield

ch07/ArrayExamples.java

@@ -30,6 +30,7 @@ public static void main(String[] args) {
             System.out.println(counts[i]);
         }
 
+        // displaying arrays
         int[] array = {1, 2, 3, 4};
         printArray(array);
 
@@ -49,9 +50,9 @@ public static void main(String[] args) {
         // copying with Arrays class
         double[] c = Arrays.copyOf(a, a.length);
 
-        // traversal
+        // traversing arrays
         for (int i = 0; i < a.length; i++) {
-            a[i] = Math.pow(a[i], 2.0);
+            a[i] *= a[i];
         }
 
         // search
@@ -66,33 +67,33 @@ public static void main(String[] args) {
     /**
      * Prints the elements of an array.
      */
-    public static void printArray(int[] array) {
-        System.out.print("{" + array[0]);
-        for (int i = 1; i < array.length; i++) {
-            System.out.print(", " + array[i]);
+    public static void printArray(int[] a) {
+        System.out.print("{" + a[0]);
+        for (int i = 1; i < a.length; i++) {
+            System.out.print(", " + a[i]);
         }
         System.out.println("}");
     }
 
     /**
      * Returns the index of the target in the array, or -1 if not found.
      */
-    public static int search(double[] a, double target) {
-        for (int i = 0; i < a.length; i++) {
-            if (a[i] == target) {
+    public static int search(double[] array, double target) {
+        for (int i = 0; i < array.length; i++) {
+            if (array[i] == target) {
                 return i;
             }
         }
-        return -1;
+        return -1;  // not found
     }
 
     /**
      * Returns the total of the elements in an array.
      */
-    public static double sum(double[] a) {
+    public static double sum(double[] array) {
         double total = 0.0;
-        for (int i = 0; i < a.length; i++) {
-            total += a[i];
+        for (int i = 0; i < array.length; i++) {
+            total += array[i];
         }
         return total;
     }

ch07/Doubloon.java

@@ -2,7 +2,7 @@
  * Example from the end of Chapter 7.
  */
 public class Doubloon {
-    
+
     public static boolean isDoubloon(String s) {
 
         // count the number of times each letter appears
@@ -21,10 +21,9 @@ public static boolean isDoubloon(String s) {
         }
         return true;
     }
-    
+
     public static void main(String[] args) {
-        System.out.println(isDoubloon("Mama"));
-        System.out.println(isDoubloon("Lama"));
+        System.out.println(isDoubloon("Mama"));  // true
+        System.out.println(isDoubloon("Lama"));  // false
     }
-    
 }

ch07/Histogram.java

@@ -31,8 +31,7 @@ public static int inRange(int[] a, int low, int high) {
     }
 
     public static void main(String[] args) {
-        int numValues = 8;
-        int[] array = randomArray(numValues);
+        int[] array = randomArray(8);
         ArrayExamples.printArray(array);
 
         int[] scores = randomArray(30);