Java Example to Demonstrate the use of Package.

Put both the Following Examples classes in a package called Measures.
Define a class to represent a weight in tons, kilograms, and grams
Define a class to represent a length measured in meters, centimeters, and millimeters

Import this package into a program that calculates and displays the total weight of the following:
200 carpets—size: 4 meters by 2 meters 9 centimeters, that weigh 1.25 kilograms per square meter;
and 60 carpets—size: 3 meters 57 centimeters by 5 meters, that weigh 1.05 kilograms per square meter.

Make sure that the source and class files for mcmLength and tkgWeight Are not in the same directory as this file. Otherwise those classes will beused rather than the ones in the Measures package

To compile this program the compiler needs to know where the Measures packages is. If the current directory contains Carpets.java and Measures is a subdirectory of this, you can compile Carpets by using the -classpath option like this:

javac -classpath . Carpets.java

If Measures is not a subdirectory of the current directory, you just need to add the path to the directory that contains Measures to -classpath. Note that you still need the period in the classpath, otherwise the compiler will not be able to find Carpets.java.

import Measures.tkgWeight;
import Measures.mcmLength;

public class Carpets {
  public static void main(String args[]) {
    mcmLength[] carpetLengths = { new mcmLength(4,0,0), new mcmLength(3,57,0) };
    mcmLength[] carpetWidths = { new mcmLength(2,9,0), new mcmLength(5,0,0) };
    double[] carpetWtPerSqM = { 1.25, 1.05 };                          // Weight per sq m of carpets
    int[] carpetCounts = { 200, 60 };


    tkgWeight carpetWeight = null;                                    // Store for reference to weight of a carpet
    double carpetArea = 0.0;                                          // Store for area of a carpet


    for(int i = 0 ; i < carpetLengths.length ; ++i) {
      // Since we want areas in square meters it is easiest to calculate them directly
      carpetArea = carpetLengths[i].toMeters()*carpetWidths[i].toMeters();

      carpetWeight = new tkgWeight(carpetWtPerSqM[i]*carpetArea);

      System.out.println("\nCarpet " + (i + 1) + ": Size = " + carpetLengths[i] + " by "+ carpetWidths[i]);
      System.out.println("        " + "  Weight per sq. m. = " + carpetWtPerSqM[i]);
      System.out.println("        " + "  Area = " + carpetArea + " sq. m.");
      System.out.println("        " + "  Weight = " + carpetWeight);

      System.out.println("        " + "  Weight of " + carpetCounts[i] + " carpets = " + carpetWeight.multiply(carpetCounts[i]));

    }
  }
}