COP3337
  Section U05
  Spring 2017


                      A Program for Hw #2
                      ===================



  I. The Circle Class:
  --------------------


  public class Circle implements Figure
  {
      // the radius
      private double radius;
    
      // construct a circle with a given radius
      public Circle(double r)
      {
          radius = r;
      }        
    
      // @return the radius
      public double getRadius()
      {
          return radius;
      }        
    
      // @return the perimeter
      public double getPerimeter()
      {
       	  // Here I use the Math.PI constant  	
          return 2 * Math.PI * radius;
      }        
    
      // @return the area
      public double getArea()
      {
          return Math.PI * radius * radius;
      }        
  }

  II. The Driver:
  ---------------

  public class Driver
  {
      //test some figures
      public static void main(String[] args)
      {
          System.out.println("TESTING FIGURES");
          System.out.println("===============\n\n\n");

          // form an array of figures
          System.out.println("We form an array of 6 figures");
          Figure[] set1 = new Figure[6];
          set1[0] = new Circle(1);
          set1[1] = new Triangle(3, 4, 5);
          try
          {
              set1[2] = new Triangle(3, 6, 2);
          }
          catch (IllegalArgumentException e)
          {
              System.out.println("We try to form an illegal triangle");
          }
    
          set1[2] = new Parallelogram(1,2,Math.PI / 3);
          set1[3] = new Square(1);
          set1[4] = new Triangle(5, 12, 13);
          set1[5] = new Circle(5);
        
          System.out.println("The array is ");
          printArray(set1);

          // find the figures with the largest area, largest perimeter,
          // smallest area, smallest perimeter
          Figure smallArea = getSmallestArea(set1);
          Figure bigArea = getLargestArea(set1);
          Figure smallPerimeter = getSmallestPerimeter(set1);
          Figure bigPerimeter = getLargestPerimeter(set1);

          // print these figures
          System.out.print("\nThe figure with a largest perimeter is ");
          printFig(bigPerimeter);
          System.out.print("\nThe figure with a smallest perimeter is ");
          printFig(smallPerimeter);
          System.out.print("\nThe figure with a largest area is ");
          printFig(bigArea);
          System.out.print("\nThe figure with a smallest area is ");
          printFig(smallArea);
      }
 
      // print an array of figures
      // if the array is null or empty print the message "The array is empty"
      // otherwise print 2 lines
      // that displays the shape, the fields, the perimeter and the area
      // of each item in the array
      public static void printArray(Figure[] figs)
      {
          // check for null or empty array
          if (figs == null || figs.length == 0)
          {
              System.out.println("The array is empty.\n");
              return;
          }
        
          // print the array
          for (int i = 0; i < figs.length; i++)
          {    
              System.out.print("array [ " + i + " ] is ");
              printFig(figs[i]);
          }    
      }

      // print the shape, the fields, the perimeter and the area
      // of fig
      // if fig = null, write null
      public static void printFig(Figure fig)
      {
          if (fig == null)
          {
             System.out.println(" null.");
             return;
          }
          if (fig instanceof Circle)
          {
              Circle c = (Circle) fig; // cast to circle
              System.out.println(" a circle of radius " + c.getRadius() + " .");
          }
          else if (fig instanceof Square)
          {
              Square sq = (Square) fig; // cast to square
              System.out.println(" a square of side " + sq.getSide() + " .");
          }
          else if (fig instanceof Triangle)   
          {
              Triangle t = (Triangle) fig; // cast to triangle
              System.out.println(" a triangle with sides " + t.getSide1() + ", " 
                  + t.getSide2()+ ", and " + t.getSide3() + " .");
          }
          else if (fig instanceof Parallelogram)
          {
              Parallelogram p = (Parallelogram) fig;
              System.out.println(" a parallelogram with sides " + p.getSide1() + 
                  " and " + p.getSide2() + " and angle " + p.getAngle() + " .");
          }
          else // unknown figure
          {
              System.out.println(" unknown figure");
              return;
          }
          // print the perimeter and the area of fig         
          System.out.println("Its perimeter is " + fig.getPerimeter() + 
              " and its area is " + fig.getArea() + " .\n");
      }
     
      // return a reference to a figure with the largest perimeter
      // among all figures of arr
      // if arr is null or empty return null
      public static Figure getLargestPerimeter(Figure[] arr)
      {
          if (arr == null || arr.length == 0)
             return null;
          Figure bigPerimeter = null;
          for (Figure fig : arr)
              if (fig != null && (bigPerimeter == null || 
                  bigPerimeter.getPerimeter()< fig.getPerimeter() ))
                  // update bigPerimeter
                  bigPerimeter = fig;
          return bigPerimeter;
      }

      // return a reference to a figure with the smallest perimeter
      // among all figures of arr
      // if arr is null or empty return null
      public static Figure getSmallestPerimeter(Figure[] arr)
      {
          if (arr == null || arr.length == 0)
             return null;
          Figure smallPerimeter = null;
          for (Figure fig : arr)
              if (fig != null && (smallPerimeter == null || 
                  smallPerimeter.getPerimeter() >  fig.getPerimeter() ))
                  // update bigPerimeter
                  smallPerimeter = fig;
          return smallPerimeter;     
      }

      // return a reference to a figure with the largest area
      // among all figures of arr
      // if arr is null or empty return null
      public static Figure getLargestArea(Figure[] arr)
      {
          if (arr == null || arr.length == 0)
             return null;
          Figure bigArea = null;
          for (Figure fig : arr)
              if (fig != null && (bigArea == null || 
                  bigArea.getArea()< fig.getArea() ))
                  // update bigPerimeter
                  bigArea = fig;
          return bigArea;
      }

      // return a reference to a figure with the smallest are
      // among all figures of arr
      // if arr is null or empty return null
      public static Figure getSmallestArea(Figure[] arr)
      {
          if (arr == null || arr.length == 0)
             return null;
          Figure smallArea = null;
          for (Figure fig : arr)
              if (fig != null && ( smallArea == null || 
                  smallArea.getArea() >  fig.getArea() ))
                  // update bigPerimeter
                  smallArea = fig;
          return smallArea;
      }
  }  // end class



  III. The Interface Figure:
  --------------------------

  public interface Figure
  {
      double getPerimeter(); // the perimeter
      double getArea(); // the area

  }

  IV. The Parallelogram Class:
  ----------------------------

  public class Parallelogram implements Figure
  {
      private double a, b; // the 2 sides
      private double angle; // the angle between and b in radians

      // form a parallelogram with 2 sides and the angle between them
      // @param s1 and s2 are the 2 sides
      // @param ang is the angle
      public Parallelogram(double s1, double s2, double ang )
      {
          a = s1;
          b = s2;
          angle = ang;
      }

      // methods that retrieve the fields
      public double getSide1()
      {
          return a;
      }

      public double getSide2()
      {
          return b;
      }

      public double getAngle()
      {
          return angle;
      }


      // @return the perimeter
      public double getPerimeter()
      {
          return 2.0 * (a + b);
      }

      // @return the area
      public double getArea()
      {
          return a * b * Math.sin(angle);
      }

  }


  V. The Square Class:
  --------------------

  public class Square implements Figure
  {
      //the field
      private double side; // the side

      // the constructor
      // build a square with side s
      public Square (double s)
      {
          side = s;
      }

      // @return the side
      public double getSide()
      {
          return side;
      }

      // @return the area
      public double getPerimeter()
      {
          return 4 * side;
      }

      // @return the area
      public double getArea()
      {
          return side * side;
      }
  }

  VI. The Triangle Class:
  -----------------------

  public class Triangle implements Figure
  {
      // the fields
      private double a, b, c; // the 3 fields

      // the constructor
      // form a triangle with sides s1,s2,s3
      // if s1,s2,s3 do not form a triangle, throw an
      // IllegalArgumentException
      public Triangle(double s1, double s2, double s3)
      {
          if ( s1 + s2 <= s3 || s2 + s3 <= s1 || s3 + s1 <= s2)
             throw new IllegalArgumentException("The numbers do not form " +
                "a triangle");
          // set the sides
          a = s1;
          b = s2;
          c = s3;
      }

      // methods that return the 3 sides
      public double getSide1()
      {
          return a;
      }

      public double getSide2()
      {
          return b;
      }

      public double getSide3()
      {
          return c;
      }

      // @ return the perimeter
      public double getPerimeter()
      {
          return a + b + c;
      }

      // @return the area
      public double getArea()
      {
          double p = (a + b+ c) / 2.0;
          return Math.sqrt( p * (p-a) * (p-b) * (p-c));
      }

  }  // end class

  VII. The output:
  ----------------

  run:
  TESTING FIGURES
  ===============



  We form an array of 6 figures
  We try to form an illegal triangle
  The array is 
  array [ 0 ] is  a circle of radius 1.0 .
  Its perimeter is 6.283185307179586 and its area is 3.141592653589793 .

  array [ 1 ] is  a triangle with sides 3.0, 4.0, and 5.0 .
  Its perimeter is 12.0 and its area is 6.0 .

  array [ 2 ] is  a parallelogram with sides 1.0 and 2.0 and angle 1.0471975511965976 .
  Its perimeter is 6.0 and its area is 1.7320508075688772 .

  array [ 3 ] is  a square of side 1.0 .
  Its perimeter is 4.0 and its area is 1.0 .

  array [ 4 ] is  a triangle with sides 5.0, 12.0, and 13.0 .
  Its perimeter is 30.0 and its area is 30.0 .

  array [ 5 ] is  a circle of radius 5.0 .
  Its perimeter is 31.41592653589793 and its area is 78.53981633974483 .


  The figure with a largest perimeter is  a circle of radius 5.0 .
  Its perimeter is 31.41592653589793 and its area is 78.53981633974483 .


  The figure with a smallest perimeter is  a square of side 1.0 .
  Its perimeter is 4.0 and its area is 1.0 .


  The figure with a largest area is  a circle of radius 5.0 .
  Its perimeter is 31.41592653589793 and its area is 78.53981633974483 .


  The figure with a smallest area is  a square of side 1.0 .
  Its perimeter is 4.0 and its area is 1.0 .

  BUILD SUCCESSFUL (total time: 0 seconds)