1. A company wants to transmit data over the telephone, but is concerned that its phones could be tapped. All of the data are transmitted as four-digit integers. The company has asked you to write a program that encrypts the data so that it can be transmitted more securely. Your program should read a four-digit integer and encrypt it as follows: Replace each digit by (the sum of that digit plus 7) modulus 10. Then, swap the first digit with the third, swap the second digit with the fourth and print the encrypted integer. 2. A parking garage charges a £2.00 minimum fee to park for up to three hours. The garage charges an additional £0.50 per hour for each hour or part thereof in excess of three hours. The maximum charge for any given 24-hour period is £10.00. Assume that no car parks for longer than 24 hours at a time. Write a program that calculates and prints the parking charges for each of three customers who parked their cars in this garage yesterday. You should enter the number of hours parked for each customer. Your program should print the results in a neat tabular format and should calculate and print the total of yesterday's receipts. The program should use the function calculateCharges to determine the charge for each customer. Your output should appear in the following format: Enter the hours parked for three cars: 1.5 4.0 24.0 Car Hours Charge 1 1.5 2.00 2 4.0 2.50 3 24.0 10.00 TOTAL 29.5 14.50 Hints: Use a for loop to prompt the user for the number of hours parked for each of the three customers. Declare variables to store the total number of hours and the total charges for each customer. The variables for all charges and numbers of hours should be of type double. Function calculateCharges should use a nested if else statement to determine the customer charge.
3. Package-delivery services, such as FedEx®, DHL® and UPS®, offer a number of different shipping options, each with specific costs associated. Create an inheritance hierarchy to represent various types of packages. Use Package as the base class of the hierarchy, then include classes TwoDayPackage and OvernightPackage that derive from Package. Base class Package should include data members representing the name, address, city, state and ZIP code for both the sender and the recipient of the package, in addition to data members that store the weight (in ounces) and cost per ounce to ship the package. Package's constructor should initialize these data members. Ensure that the weight and cost per ounce contain positive values. Package should provide a public member function calculateCost that returns a double indicating the cost associated with shipping the package. Package's calculateCost function should determine the cost by multiplying the weight by the cost per ounce. Derived class TwoDayPackage should inherit the functionality of base class Package, but also include a data member that represents a flat fee that the shipping company charges for two-day-delivery service. TwoDayPackage's constructor should receive a value to initialize this data member. TwoDayPackage should redefine member function calculateCost so that it computes the shipping cost by adding the flat fee to the weight-based cost calculated by base class Package's calculateCost function. Class OvernightPackage should inherit directly from class Package and contain an additional data member representing an additional fee per ounce charged for overnight- delivery service. OvernightPackage should redefine member function calculateCost so that it adds the additional fee per ounce to the standard cost per ounce before calculating the shipping cost. Write a test program that creates objects of each type of Package and tests member function calculateCost. 4. Suppose we wish to process survey results that are stored in a file. This exercise requires two separate programs. First, create a program that prompts the user for survey responses and outputs each response to a file. Use an ofstream to create a file called "numbers.txt". Then create a program to read the survey responses from "numbers.txt". The responses should be read from the file by using an ifstream. Input one integer at a time from the file. The program should continue to read responses until it reaches the end of file. The results should be output to the text file "output.txt". [Hint: The second program will use both ifstream and ofstream objects, the first for reading responses from numbers.txt and the second for writing frequency counts to output.txt.] 5. Many businesses' Web sites contain shopping-cart applications, which allow customers to buy items conveniently on the Web. The sites record what the consumer wants to purchase and provide an easy, intuitive way to shop online. They do so by using an electronic shopping cart, just as people would use physical shopping carts in retail stores. As users add items to their shopping carts, the sites update the carts' contents. When users "check out," they pay for the items in their shopping carts. You must implement a shopping cart which allows users to purchase digital satellite receivers from a fictitious satellite store that sells four digital satellite receivers. Your application may uses four scripts, two server-side files and cookies
