Chapter 21, Problem 2PP

Program Plan Intro

To print letter frequencies

Program plan:

• In a file “FrequencyMap.java”, create a class “FrequencyMap”,
  • Declare an array variable.
  • Define the constructor to initialize the values.
  • Define the method “getFrequency()” to get the frequency of the specified letter.
  • Define the method “add()” to add a letter to be counted.
• In a file “FrequencyCounter.java”, import the necessary packages and create a class “FrequencyCounter”,
  • Define the method “main()”,
    • Create a Scanner object.
    • Prompt the user for a file name.
    • Get the file location from the user.
    • Execute “try” statement,
      • Create an object for “FrequencyMap”.
      • Set the Boolean value to “done”.
      • Execute loop if not done,
        • Read the character.
        • If “-1”,
        • • Set the Boolean value to true.
        • Otherwise, check if there is a letter,
        • • Call the method “add()” to add a letter to be counted.
      • Close he file reader.
      • Execute a loop,
        • Print the frequencies.
    • Catch if exception occurs,
      • Handle the exception.