Java Exercises

Recap

Read

• OOP Concepts
  • no need to read about "Pillars of OOP"
• Classes
• Methods
• Strings
• Lists
  • will be needed for the last exercise

Watch

• thenewboston
  • videos 14, 15, 16, 38, 39, 40, 46, 47

Exercises

Binary to Decimal Converter

Write a program to convert a binary number (contained in a String, such that each character in the string is either 0 or 1) to a decimal (as an int). Implement the program in 2 parts:

• a method which receives a String binary and returns an int decimal number
• a main which reads a binary number from the user and uses said method to convert the number and display the result returned from it.

Don't use any built-in utilities which already implement the conversion, implement it yourselves. You can read here about how to perform the conversion.

For example: binary "101" is equal to decimal 5.

Reverse a String

Write a program which reverses the order of characters in a String. Implement the program in 2 parts:

• a method which receives a String to reverse, and returns a reversed String
• a main which reads the String from the user and uses said method to reverse the String and print the results.

For example: "This is the greatest plan" reversed is "nalp tsetaerg eht si sihT".

Ceaser Cipher

Write a program capable of encrypting and decrypting Strings using the Ceaser Cipher. Implement the cipher in 2 programs - one for encrypting and one for decrypting. Each program will be made up of:

• a method for encrypting or decrypting a String.
• a main which reads a String from the user and uses said method to encrypt or decrypt the String and prints the result.

For some explanation of the cipher, read here. But basically the idea is that each character is replaced by another character. That character is selected by the cipher, which is basically a shift of the alphabet. So if shift=2, we would get that a = c.

Select your own cipher (i.e. shift).

Inventory

Create a shop inventory program. This is an OOP project, and you are expected to create classes. The program should:

• keep track of products in the shop
• allow users to add products
  • add quantity to the product. If the product already exists in the shop, add quantity to the existing product; if does not exist, create a new product in the shop.
• allow users to remove products
  • remove some quantity from the product. If the quantity is 0, the product is removed from the shop.
• allow users query a list of products
  • print information about all the products in the shop

You should divide your program to the following classes:

• Product: holding information about a single product.
  • Name of the product
  • Amount of the product
  • Getters and setters for name and amount
• Shop: holding information about the entire shop.
  • List of the products in the shop
  • Getters and setters for the list
• Main: the main program.
  • all the things regarding user interaction

Interaction with the program will be done via a menu. Options will be displayed to the user, allowing him to select what to do with the program. Example:

1. View products
2. Add Product
3. Remove Product
4. Exit
Select: 

The user will then enter a number indicating the action to perform. The program will then move to a sub-menu depending on the action.

1. View products
2. Add Product
3. Remove Product
4. Exit
Select: 2

Enter Product Name: Whip
Enter Product Quantity: 5

Upon finishing work with the sub-menu, the program will return to the main menu.

You do have some freedom to implement things a bit differently, but I do expect at least the minimum described here.