/* Triangle.java
 * In this file, we implement all the necessary functionality
 * for triangles.  We need to specify the attributes and operations.
 * The attributes are simply the 3 sides of the triangle.
 */
public class Triangle
{
  private int shortest;		// These attributes could have been double.
  private int middle;
  private int longest;

  // Constructor:  Given 3 values, initialize the attributes.  To simplify
  // the implementation, let's assume that the 3 parameters are already
  // in ascending order.  Otherwise we'd have to enumerate every possible
  // permutation (6 cases) using if statements.
  public Triangle (int a, int b, int c)
  {
    shortest = a;
    middle = b;
    longest = c;
  }

  // isValid - Is the longest side less than the sum of the other 2 sides?
  public boolean isValid()
  {
    return longest < middle + shortest;
  }

  // isEquilateral - We only need to check the sides of extreme length.  :)
  // In math, this is called the "squeeze theorem":  If a <= b <= c and you
  //   know that a == c, then b must be equal as well.
  public boolean isEquilateral()
  {
    return longest == shortest;
  }

  // Let's assume that an equilateral triangle may also be isosceles.
  // (It wouldn't be hard to change this assumption.)
  public boolean isIsosceles()
  {
    return longest == middle || middle == shortest;
  }

  // Finally, about the angles.  Use the pythagorean theorem for right, etc.
  public boolean isRight()
  {
    return longest*longest == middle*middle + shortest*shortest;
  }

  public boolean isObtuse()
  {
    return longest*longest > middle*middle + shortest*shortest;
  }

  // This function performs a calculation and returns a number.
  public int findPerimeter()
  {
    return shortest + middle + longest;
  }

  // Finally, it's a nice idea to have a way to print out an object.
  // We do this by writing a toString() function.
  // I'll just put the 3 lengths inside parentheses.
  public String toString()
  {
    return "(" + shortest + ", " + middle + ", " + longest + ")";
  }
}