Update solutions

Author: Sven97

src/Chapter05/Exercise0541_Occurrence_of_max_numbers.java

@@ -0,0 +1,44 @@
+/**
+ * (Occurrence of max numbers) Write a program that reads integers, finds the largest
+ * of them, and counts its occurrences. Assume the input ends with number 0. Suppose
+ * you entered 3 5 2 5 5 5 0; the program finds that the largest is 5 and the
+ * occurrence count for 5 is 4.
+ * (Hint: Maintain two variables, max and count. max stores the current max number
+ * and count stores its occurrences. Initially, assign the first number to max and 1 to
+ * count. Compare each subsequent number with max. If the number is greater than
+ * max, assign it to max and reset count to 1. If the number is equal to max, increment
+ * count by 1.)
+ *
+ * Enter numbers: 3 5 2 5 5 5 0
+ * The largest number is 5
+ * The occurrence count of the largest number is 4
+ *
+ * Created by Sven on 06/05/19.
+ */
+package Chapter05;
+
+import java.util.Scanner;
+
+public class Exercise0541_Occurrence_of_max_numbers {
+    public static void main(String[] args) {
+        Scanner input = new Scanner(System.in);
+        System.out.print("Enter numbers: ");
+
+        int next = input.nextInt();
+        int max = next;
+        int count = 1;
+
+        while (next != 0) {
+            next = input.nextInt();
+            if (next > max) {
+                max = next;
+                count = 1;
+            } else if (next == max) {
+                count++;
+            }
+        }
+
+        System.out.println("The largest number is " + max);
+        System.out.println("The occurrence count of the largest number is " + count);
+    }
+}

src/Chapter05/Exercise0542_Financial_application_find_the_sales_amount.java

@@ -0,0 +1,37 @@
+/**
+ * (Financial application: find the sales amount) Rewrite Programming Exercise 5.39
+ * as follows:
+ * ■ Use a while loop instead of a do-while loop.
+ * ■ Let the user enter COMMISSION_SOUGHT instead of fixing it as a constant.
+ *
+ * Created by Sven on 06/05/19.
+ */
+package Chapter05;
+
+import java.util.Scanner;
+
+public class Exercise0542_Financial_application_find_the_sales_amount {
+    public static void main(String[] args) {
+        Scanner input = new Scanner(System.in);
+
+        double commission = 0.0;
+        double salesAmount = 0.0;
+
+        System.out.print("Enter commission amount: ");
+        double COMMISSION_SOUGHT = input.nextInt();
+
+        while (salesAmount - commission < COMMISSION_SOUGHT) {
+            salesAmount += 0.01;
+
+            if (salesAmount > 10000.0) {
+                commission = 700.0 + (salesAmount - 10000.0) * 0.1;
+            } else if (salesAmount > 5000.0) {
+                commission = 300.0 + (salesAmount - 5000.0) * 0.08;
+            } else {
+                commission = salesAmount * 0.06;
+            }
+        }
+
+        System.out.println("You need $" + (int) salesAmount + " sales amount to make a commission of $" + COMMISSION_SOUGHT);
+    }
+}

src/Chapter05/Exercise0543_Math_combinations.java

@@ -0,0 +1,27 @@
+/**
+ * (Math: combinations) Write a program that displays all possible combinations
+ * for picking two numbers from integers 1 to 7. Also display the total number of
+ * all combinations.
+ *
+ * 1 2
+ * 1 3
+ * ...
+ * ...
+ * The total number of all combinations is 21
+ *
+ * Created by Sven on 06/05/19.
+ */
+package Chapter05;
+
+public class Exercise0543_Math_combinations {
+    public static void main(String[] args) {
+        int count = 0;
+        for (int i = 1; i < 8; i++) {
+            for (int j = i + 1; j < 8; j++) {
+                System.out.println(i + " " + j);
+                count++;
+            }
+        }
+        System.out.println("The total number of all combinations is " + count);
+    }
+}

src/Chapter05/Exercise0544_Computer_architecture_bit_level_operations.java

@@ -0,0 +1,32 @@
+/**
+ * (Computer architecture: bit-level operations) A byte value is stored in 8 bits. Write
+ * a program that prompts the user to enter a byte integer and displays the 8 bits for
+ * the integer. Here are sample runs:
+ *
+ * Enter an integer: 5
+ * The 8 bits are 00000101
+ *
+ * Enter an integer: –5
+ * The 8 bits are 11111011
+ *
+ * (Hint: You need to use the bitwise right shift operator (>>) and the bitwise AND
+ * operator (&), which are covered in Appendix G, Bitwise Operations.)
+ *
+ * Created by Sven on 06/05/19.
+ */
+package Chapter05;
+
+import java.util.Scanner;
+
+public class Exercise0544_Computer_architecture_bit_level_operations {
+    public static void main(String[] args) {
+        Scanner input = new Scanner(System.in);
+        System.out.print("Enter an integer: ");
+        int number = input.nextInt();
+
+        System.out.print("he 8 bits are ");
+        for (int i = 7; i >= 0; i--) {
+            System.out.print((number >> i) & 1);
+        }
+    }
+}

src/Chapter05/Exercise0545_Statistics_compute_mean_and_standard_deviation.java

@@ -0,0 +1,41 @@
+/**
+ * (Statistics: compute mean and standard deviation) In business applications, you
+ * are often asked to compute the mean and standard deviation of data. The mean is
+ * simply the average of the numbers. The standard deviation is a statistic that tells
+ * you how tightly all the various data are clustered around the mean in a set of data.
+ * For example, what is the average age of the students in a class? How close are the
+ * ages? If all the students are the same age, the deviation is 0.
+ * Write a program that prompts the user to enter 10 numbers and displays the mean
+ * and standard deviations of these numbers using the following formula:
+ *
+ * Here is a sample run:
+ * Enter 10 numbers: 1 2 3 4.5 5.6 6 7 8 9 10
+ * The mean is 5.61
+ * The standard deviation is 2.99794
+ *
+ * Created by Sven on 06/05/19.
+ */
+package Chapter05;
+
+import java.util.Scanner;
+
+public class Exercise0545_Statistics_compute_mean_and_standard_deviation {
+    public static void main(String[] args) {
+        Scanner input = new Scanner(System.in);
+        System.out.print("Enter 10 numbers: ");
+
+        double sum = 0.0;
+        double square_sum = 0.0;
+        int count = 0;
+
+        for (int i = 0; i < 10; i++) {
+            double next = input.nextDouble();
+            sum += next;
+            square_sum += Math.pow(next, 2);
+            count++;
+        }
+
+        System.out.println("The mean is " + sum / count);
+        System.out.println("The standard deviation is " + Math.sqrt((square_sum - (Math.pow(sum, 2) / count)) / (count - 1)));
+    }
+}

src/Chapter05/Exercise0546_Reverse_a_string.java

@@ -0,0 +1,28 @@
+/**
+ * (Reverse a string) Write a program that prompts the user to enter a string and
+ * displays the string in reverse order.
+ *
+ * Enter a string: ABCD
+ * The reversed string is DCBA
+ *
+ * Created by Sven on 06/05/19.
+ */
+package Chapter05;
+
+import java.util.Scanner;
+
+public class Exercise0546_Reverse_a_string {
+    public static void main(String[] args) {
+        Scanner input = new Scanner(System.in);
+        System.out.print("Enter a string: ");
+        
+        String str = input.next();
+        String reverse_str = "";
+
+        for (int i = str.length() - 1; i >= 0; i--) {
+            reverse_str += str.charAt(i);
+        }
+        System.out.print("The reversed string is " + reverse_str);
+
+    }
+}