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Example: complex number

Example: complex number. public class ComplexNumber { private double real; private double img; // override default constructor public ComplexNumber () { real = 0.0; img = 0.0; } // a more meaningful constructor

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Example: complex number

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  1. Example: complex number public class ComplexNumber { private double real; private double img; // override default constructor public ComplexNumber () { real = 0.0; img = 0.0; } // a more meaningful constructor public ComplexNumber (double x, double y) { real = x; img = y; }

  2. Example: complex number // compute magnitude public double Magnitude () { return (Math.sqrt(real*real + img*img)); } // compute argument public double Argument () { return (Math.atan (img/real)); } // add a complex number to it public void Add (ComplexNumber c) { real += c.GetReal(); img += c.GetImg(); }

  3. Example: complex number // add the Get/Set methods public double GetReal () { return real; } public double GetImg () { return img; } public void SetReal (double x) { real = x; } public void SetImg (double x) { img = x; } } // end class

  4. Example: complex number class ComplexNumberTester { public static void main (String a[]) { int n = 10, i; // construct 1+i ComplexNumber c1 = new ComplexNumber (1, 1); // construct 1-i ComplexNumber c2 = new ComplexNumber (1, -1); // add these two c1.Add(c2); // array of complex numbers ComplexNumber rootsOfUnity[] = new ComplexNumber[n];

  5. Example: complex number for (i=0; i<n; i++) { rootsOfUnity[i] = new ComplexNumber (Math.cos (2*i*Math.PI/n), Math.sin (2*i*Math.PI/n)); } } }

  6. Example: room public class Room { private int numDoors; private int numWindows; private int numLamps; private int numFans; private String wallColor; // Override default constructor public Room () { numDoors = 1; numWindows = 2; numLamps = 1; numFans = 1; wallColor = “White”; }

  7. Example: room // a richer constructor public Room (int nD, int nW, int nL, int nF, String wC) { numDoors = nD; numWindows = nW; numLamps = nL; numFans = nF; wallColor = new String (wC); // what is the problem with wallColor = wC ? }

  8. Example: room // might want to add a fan public void AddFan (int howmany) { numFan += howmany; } // might want to re-paint wall public void PaintWall (String whichcolor) { wallColor = new String (whichcolor); } }

  9. Example: room public class House { // array of rooms private Room rooms[]; // might have some people private int numHuman; // might have some animals private int numPets; // might have a garden private boolean isThereAGarden; // might have a swimming pool private boolean isThereASwimmingPool;

  10. Example: room // override default constructor public House () { rooms = new Room[1]; rooms[0] = new Room ();// default room numHuman = 1; numPets = 1; isThereAGarden = true; isThereASwimmingPool = false; }

  11. Example: room // More useful constructor public House (int nD[], int nW[], int nL[], int nF[], String wC[], int nH, int nP, boolean g, boolean sp) { int numRooms = nD.length; int i; rooms = new Room[numRooms]; for (i=0; i<numRooms; i++) { rooms[i] = new Room (nD[i], nW[i], nL[i], nF[i], wC[i]); } numHuman = nH;

  12. Example: room numPets = nP; isThereAGarden = g; isThereASwimmingPool = sp; } // might want to add a fan in some room public void AddFan (int roomID) { rooms[roomID].AddFan (1); } // paint wall of some room public void PaintWall (int roomID, String color) { rooms[roomID].PaintWall (color); }

  13. Example: room // add a pet public void BringPet () { numPets++; } // get reference to a room public Room GetRoom (int roomID) { return rooms[roomID]; } }

  14. Example: room class HouseBuilder { public static void main (String a[]) { House myHouse = new House (); // repaint wall myHouse.GetRoom(0).PaintWall (“Golden”); // could paint wall of room[0] as below also // myHouse.PaintWall (0, “Golden”); // bring a pet myHouse.BringPet(); } }

  15. Example: polynomial A polynomial is an aggregate of algebraic terms Each term has a coefficient and an array of indices, one for each variable Need three classes: an AlgebraicTerm class, a polynomial class, and a top level class implementing main

  16. Example:Algebraic Term public class AlgebraicTerm { private double coefficient; private int[] index; // General constructor public AlgebraicTerm (double coeff, int[] ind) { int numVar = ind.length; int i; index = new int[numVar]; for (i=0; i<numVar; i++) { index[i] = ind[i]; } coefficient = coeff; } // continued in next slide

  17. // Special constructor for univariate // Note: method overloading public AlgebraicTerm (double coefficient, int index) { this.coefficient = coefficient; this.index = new int[1]; this.index[0] = index; } // continued in next slide

  18. public double Evaluate (double[] v) { int i; double value = coefficient; for (i=0; i<index.length; i++) { // Could say this.index[i] // But not needed value *= Math.pow(v[i], index[i]); } return value; } // continued in next slide

  19. public AlgebraicTerm Add (AlgebraicTerm aterm) { AlgebraicTerm rterm = null; if (checkConsistency (aterm)) { rterm = new AlgebraicTerm (coefficient+aterm.GetCoefficient(), index); } return rterm; } // continued in next slide

  20. public double GetCoefficient () { return coefficient; } public int[] GetIndex () { return index; } // continued in next slide

  21. private boolean checkConsistency (AlgebraicTerm aterm) { return (index.length == aterm.GetIndex().length); } public static void main(String arg[ ]){ int [ ] a = {3,2,1}; double c=2.5; double [ ] b ={2.0, 3.0, 1.0}; AlgebraicTerm A = new AlgebraicTerm(c,a); System.out.println(A.Evaluate(b)); Example(); }

  22. public static void Example(){ int[] a= {2,3,1}; double c= 2.5; AlgebraicTerm A = new AlgebraicTerm(c,a); a[0]=1; a[1]=2; a[2]=3; c=3.2; AlgebraicTerm B = new AlgebraicTerm(c,a); System.out.println(A.coefficient); for (int i=0;i<A.index.length;i++) System.out.println(A.index[i]); System.out.println(B.coefficient); for (int i=0;i<A.index.length;i++) System.out.println(B.index[i]); double [] b={3.0,2.0,1.0}; System.out.println(A.Evaluate(b)); System.out.println(B.Evaluate(b)); } }

  23. public class ATExample{ public static void main(String arg[]){ AlgebraicTerm C= new AlgebraicTerm(2.0,4); C.Example(); int[] a= {2,3,1}; double c= 2.5; AlgebraicTerm A = new AlgebraicTerm(c , a); System.out.println(A.GetCoefficient()); for (int i=0;i<A.GetIndex().length;i++) System.out.println(A.GetIndex()[i]); double [] b={3.0,2.0,1.0}; System.out.println(A.Evaluate(b)); } }

  24. Example: polynomial public class Polynomial { AlgebraicTerm [] terms; public Polynomial (double [] coefficient, int [] index[], int numVar) { int nTerms = coefficient.length; int i; terms = new AlgebraicTerm[nTerms]; for (i=0; i<nTerms; i++) { terms[i] = new AlgebraicTerm (coefficient[i], index[i]); } } // continued in next slide

  25. Example: polynomial public Polynomial (AlgebraicTerm [] t) { int nTerms = t.length; int i; terms = new AlgebraicTerm[nTerms]; for (i=0; i<nTerms; i++) { terms[i] = t[i]; } } // continued in next slide

  26. Example: polynomial public void SetTerms (AlgebraicTerm[] terms) { this.terms = terms; } public AlgebraicTerm[] GetTerms () { return terms; } // continued in next slide

  27. Example: polynomial public double Evaluate (double[] v) { int nTerms = terms.length; int i; double value=0; for (i=0; i<nTerms; i++) { value += terms[i].Evaluate(v); } return value; } // continued in next slide

  28. Example: polynomial public Polynomial Add (Polynomial p) { Polynomial q = null; AlgebraicTerm[] aterms; int i; if (checkConsistency(p)) { // Assume ordered terms aterms = new AlgebraicTerm [terms.length]; for (i=0; i<terms.length; i++) { aterms[i] = terms[i].Add (p.GetTerms()[i]); } q = new Polynomial (aterms); } return q; } // continued in next slide

  29. Example: polynomial private boolean checkConsistency (Polynomial p) { return (p.GetTerms().length == terms.length); } } // end of polynomial class; continued in next slide

  30. Example: polynomial class PolynomialExample { public static void main (String arg[]) { double coeff[] = {1, 2, 1}; int index[][] = {{2}, {1}, {0}}; double values[] = {-2}; Polynomial perfectQ = new Polynomial (coeff, index, 1); coeff[1] = -2; Polynomial perfectQ2 = new Polynomial (coeff, index, 1); Polynomial oneMoreQ = perfectQ.Add (perfectQ2); // continued in next slide

  31. Example: polynomial swap (perfectQ, perfectQ2); System.out.println (perfectQ.Evaluate(values) + “, ” + perfectQ2.Evaluate(values)); } // end main // following method doesn’t work /* private static void swap (Polynomial P1, Polynomial P2) { AlgebraicTerm terms[] = P1.terms; P1.terms = P2.terms; P2.terms = terms; }*/ // continued in next slide

  32. Example: polynomial // Note that swap must be static because // it is called by a static method private static void swap (Polynomial P1, Polynomial P2) { AlgebraicTerm terms[] = P1.GetTerms(); P1.SetTerms (P2.GetTerms()); P2.SetTerms (terms); } } // end class

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