Chapter 8, Problem 14PP

Program Plan Intro

Program plan:

LargestCountry.java:

• Define a class named “LargestCountry”.
  • Define a function named “readCountry” with type “Country”.
    • Using the “Print” statement, prompt the user to enter the country name.
    • Using the scanner class, create an object “in” for reading the input values.
    • Using “next()” method gets the next string and store it into the variable “name”.
    • Using the “if” conditional statement, check whether the value of “name” is not equal to “quit”.
      • If the condition is true, then prompt the user to enter the country population.
      • Using the “nextInt()” method gets the next integer and store it into the variable “population”.
      • Using the “Print” statement, prompt the user to enter the country area.
      • Using the “nextDouble()” method gets the next double and store into the variable “area”.
      • Return a country “name”, “population”, and “area”.
    • Return “null”
  • Define a main function.
    • Create an object named “largestArea” of class country.
    • Create an object named “largestPopulation” of class country.
    • Create an object named “largestDensity” of class country.
    • Call the function “readCountry” and store the result into the object “b”.
    • Execute “While” block and check whether the value of “b” is not equal to “null”.
      • Using the “if” conditional statement, call the function “largerArea” and find the largest area.
        • If the condition is true, then store the largest area into the variable “largestArea”.
        • • Using the “if” conditional statement, call the function “largerPopulation” and find the largest population.
            • If the condition is true, then store the largest population into the variable “largestPopulation”.
          • Using the “if” conditional statement, call the function “largerDensity” and find the largest density.
            • If the condition is true, then store the largest density into the variable “largestDensity”.
          • Call the function “readCountry” and store the result into the object “b”.
    • Using the “Print” statement, call the function “largestArea” and display the largest area.
    • Using the “Print” statement, call the function “largestPopulation” and display the largest population.
    • Using the “Print” statement, call the function “largestDensity” and display the largest density.

Country.java:

• Define a class named “Country” for holding country information.
  • Declare three variables “name”, “population”, and “area”.
  • Create a constructor with three arguments.
    • Assign the value of the variable “name” into the variable “this.name”.
    • Assign the value of the variable “population” into the variable “this.population”.
    • Assign the value of the variable “area” into the variable “this.area”.
  • Define a function named “printCountry” and print the country name, population and area.
  • Define a double function named “getPopulationDensity”
    • Using the “if” conditional statement, check whether “area” is not equal to “0”.
      • If the condition is true, then return population density.
        • Else return “0”.
  • Define a boolean function named “largerPopulation” for finding which country has a larger population.
    • Return true if “this.population” is greater than “b.population”.
  • Define a boolean function named “largerDensity” for finding which country has larger population density.
    • Return true if “this.getPopulationDensity” is greater than “b.getPopulationDensity”.
  • Define a boolean function named “largerArea” for finding which country has a larger area.
    • Return true if “this.area” is greater than “b.area”.