lab 7

CS 160

Lab 7

Today's lab will test your knowledge of classes, methods, using the API and solving problems using the control structures you learned this week.

You will create two classes. One class will be the driver that has your main method. My main method had two lines, I created an instance of my second class, and then I called a go() method that started the program. Your second class will have several methods using whiles, switches, and do/whiles to solve the problem.

The problem:

You are to write a program that will complete the following tasks:

Start: Prompt the user to give you a sentence (String) of any kind. Constructor can handle this.
- The constructor should also create the instance of the Scanner class as a class variable so it can be used in all the methods.
After the input is set you will give the user a menu of choices that will manipulate the String
- Choice 1: Count the occurrences of a letter in the String
  - When the user chooses this choice, choice 1, you should call a method to handle the counting
  - The counting method will first prompt the user for the letter they want to find.
  - Then you will use the String methods from the API, along with a loop and if statements to count the occurence of the letter.
- Choice 2: Count the words in the String.
  - ignore white space "This is a string" and "This is a String" would both count 4 words.
  - If the user chooses 2 you should call a method that handles this.
- Choice 3: Change the original input String.
  - Just call a method that asks for new user input, and then resets your String instance field to the new user input.
- Choice 4: Exit.
According to whatever choice the user request you will use a switch statement to call the method that handles that chore.
The program will continue to run until the user chooses the exit choice. Use a while loop.
Do not use JOptionPane, use the Scanner class.

Here is a sample output of my program running. Sample Output Here are the steps the user picked to get this output.

Gave the input String
Selected count a letter and chose 's' as the letter
Counted the words.
Changed the input String to one with a bunch of spaces.
Counted the words again (notice it ignored the white space)
Chose exit

Hints:

Other things you will need to use to solve the problem.

String API - I used indexOf(String, int), charAt(int)
- on indexOf make sure you increment the int or you'll keep finding the same letter or space over and over again.
I used a do/while in the counting letters and finding words.
After I found the end of a word, I moved the index up one until the spaces ended, then incremented my counter and searched for the end of the next word.

The steps you should take to make it easier:

Go step by step.

First get the user input working.
Then get the menu to print out.
Then get the switch statement set up.
Then get exit to work.
Then get the resetting the String to work.
Then work on counting letters or words.

Compile often. Compile after each step.