/*
Learning C#
by Jesse Liberty
Publisher: O'Reilly
ISBN: 0596003765
*/
using System;
class Fraction
{
private int numerator;
private int denominator;
// create a fraction by passing in the numerator
// and denominator
public Fraction(int numerator, int denominator)
{
this.numerator=numerator;
this.denominator=denominator;
}
// overload the constructor to create a
// fraction from a whole number
public Fraction(int wholeNumber)
{
Console.WriteLine("In constructor taking a whole number");
numerator = wholeNumber;
denominator = 1;
}
// convert ints to Fractions implicitly
public static implicit operator Fraction(int theInt)
{
Console.WriteLine("Implicitly converting int to Fraction");
return new Fraction(theInt);
}
// convert Fractions to ints explicitly
public static explicit operator int(Fraction theFraction)
{
Console.WriteLine("Explicitly converting Fraction to int");
return theFraction.numerator /
theFraction.denominator;
}
// overloaded operator + takes two fractions
// and returns their sum
public static Fraction operator+(Fraction lhs, Fraction rhs)
{
// like fractions (shared denominator) can be added
// by adding thier numerators
if (lhs.denominator == rhs.denominator)
{
return new Fraction(lhs.numerator+rhs.numerator,
lhs.denominator);
}
// simplistic solution for unlike fractions
// 1/2 + 3/4 == (1*4) + (3*2) / (2*4) == 10/8
// this method does not reduce.
int firstProduct = lhs.numerator * rhs.denominator;
int secondProduct = rhs.numerator * lhs.denominator;
return new Fraction(
firstProduct + secondProduct,
lhs.denominator * rhs.denominator
);
}
// test whether two Fractions are equal
public static bool operator==(Fraction lhs, Fraction rhs)
{
if (lhs.denominator == rhs.denominator &&
lhs.numerator == rhs.numerator)
{
return true;
}
// code here to handle unlike fractions
return false;
}
// delegates to operator ==
public static bool operator !=(Fraction lhs, Fraction rhs)
{
bool equality = lhs==rhs;
return !(equality);
}
// tests for same types, then delegates
public override bool Equals(object o)
{
if (! (o is Fraction) )
{
return false;
}
return this == (Fraction) o;
}
// return a string representation of the fraction
public override string ToString()
{
String s = numerator.ToString() + "/" +
denominator.ToString();
return s;
}
}
public class TesterOverrideThree
{
static void Main()
{
Fraction f1 = new Fraction(3,4);
Fraction f2 = new Fraction(2,4);
Fraction f3 = f1 + f2;
Console.WriteLine("adding f3 + 5...");
Fraction f4 = f3 + 5;
Console.WriteLine("f3 + 5 = f4: {0}", f4.ToString());
Console.WriteLine("
Assigning f4 to an int...");
int truncated = (int) f4;
Console.WriteLine("When you truncate f4 you get {0}",
truncated);
}
}
Software Development
software development notes, main category for Cs, Java, and other programming experiences.
Overloaded operator: whether two Fractions are equal
/*
Learning C#
by Jesse Liberty
Publisher: O'Reilly
ISBN: 0596003765
*/
using System;
class Fraction
{
private int numerator;
private int denominator;
// create a fraction by passing in the numerator
// and denominator
public Fraction(int numerator, int denominator)
{
this.numerator=numerator;
this.denominator=denominator;
}
// overloaded operator+ takes two fractions
// and returns their sum
public static Fraction operator+(Fraction lhs, Fraction rhs)
{
// like fractions (shared denominator) can be added
// by adding thier numerators
if (lhs.denominator == rhs.denominator)
{
return new Fraction(lhs.numerator+rhs.numerator,
lhs.denominator);
}
// simplistic solution for unlike fractions
// 1/2 + 3/4 == (1*4) + (3*2) / (2*4) == 10/8
// this method does not reduce.
int firstProduct = lhs.numerator * rhs.denominator;
int secondProduct = rhs.numerator * lhs.denominator;
return new Fraction(
firstProduct + secondProduct,
lhs.denominator * rhs.denominator
);
}
// test whether two Fractions are equal
public static bool operator==(Fraction lhs, Fraction rhs)
{
if (lhs.denominator == rhs.denominator &&
lhs.numerator == rhs.numerator)
{
return true;
}
// code here to handle unlike fractions
return false;
}
// delegates to operator ==
public static bool operator !=(Fraction lhs, Fraction rhs)
{
return !(lhs==rhs);
}
// tests for same types, then delegates
public override bool Equals(object o)
{
if (! (o is Fraction) )
{
return false;
}
return this == (Fraction) o;
}
// return a string representation of the fraction
public override string ToString()
{
String s = numerator.ToString() + "/" +
denominator.ToString();
return s;
}
}
public class TesterOperatorOverride
{
static void Main()
{
Fraction f1 = new Fraction(3,4);
Console.WriteLine("f1: {0}", f1.ToString());
Fraction f2 = new Fraction(2,4);
Console.WriteLine("f2: {0}", f2.ToString());
Fraction f3 = f1 + f2;
Console.WriteLine("f1 + f2 = f3: {0}", f3.ToString());
Fraction f4 = new Fraction(5,4);
if (f4 == f3)
{
Console.WriteLine("f4: {0} == F3: {1}",
f4.ToString(),
f3.ToString());
}
if (f4 != f2)
{
Console.WriteLine("f4: {0} != F2: {1}",
f4.ToString(),
f2.ToString());
}
if (f4.Equals(f3))
{
Console.WriteLine("{0}.Equals({1})",
f4.ToString(),
f3.ToString());
}
}
}
overloaded operator + takes two fractions
/*
Learning C#
by Jesse Liberty
Publisher: O'Reilly
ISBN: 0596003765
*/
using System;
class Fraction
{
private int numerator;
private int denominator;
// create a fraction by passing in the numerator
// and denominator
public Fraction(int numerator, int denominator)
{
this.numerator=numerator;
this.denominator=denominator;
}
// overloaded operator + takes two fractions
// and returns their sum
public static Fraction operator+(Fraction lhs, Fraction rhs)
{
// like fractions (shared denominator) can be added
// by adding their numerators
if (lhs.denominator == rhs.denominator)
{
return new Fraction(lhs.numerator+rhs.numerator,
lhs.denominator);
}
// simplistic solution for unlike fractions
// 1/2 + 3/4 == (1*4) + (3*2) / (2*4) == 10/8
// this method does not reduce.
int firstProduct = lhs.numerator * rhs.denominator;
int secondProduct = rhs.numerator * lhs.denominator;
return new Fraction(
firstProduct + secondProduct,
lhs.denominator * rhs.denominator
);
}
// return a string representation of the fraction
public override string ToString()
{
String s = numerator.ToString() + "/" +
denominator.ToString();
return s;
}
}
public class TesterOverrideToString
{
static void Main()
{
Fraction f1 = new Fraction(3,4);
Console.WriteLine("f1: {0}", f1.ToString());
Fraction f2 = new Fraction(2,4);
Console.WriteLine("f2: {0}", f2.ToString());
Fraction f3 = f1 + f2;
Console.WriteLine("f1 + f2 = f3: {0}", f3.ToString());
}
}
Demonstrates overloading the addition operator for two class objects
/*
C# Programming Tips & Techniques
by Charles Wright, Kris Jamsa
Publisher: Osborne/McGraw-Hill (December 28, 2001)
ISBN: 0072193794
*/
//
// Plus.cs -- demonstrates overloading the addition operator for two
// class objects.
//
// Compile this program with the following command line:
// C:>csc Plus.cs
//
namespace nsOverload
{
using System;
public class PlusclsMain
{
static public void Main ()
{
clsPoint point1 = new clsPoint (12, 28, "This is part");
clsPoint point2 = new clsPoint (42, 64, " of a string");
clsPoint point3 = point1 + point2;
Console.WriteLine ("Results for point3:");
Console.WriteLine (" Point is at " + point3);
Console.WriteLine (" str = " + point3.str);
}
}
class clsPoint
{
public clsPoint () { }
public clsPoint (int x, int y, string str)
{
m_cx = x;
m_cy = y;
this.str = str;
}
private int m_cx = 0;
private int m_cy = 0;
public int cx
{
get {return (m_cx);}
set {m_cx = value;}
}
public int cy
{
get {return (m_cy);}
set {m_cy = value;}
}
public string str = "";
static public clsPoint operator +(clsPoint pt1, clsPoint pt2)
{
clsPoint point = new clsPoint();
point.cx = pt1.cx + pt2.cx;
point.cy = pt1.cy + pt2.cy;
point.str = pt1.str + pt2.str;
return (point);
}
public override string ToString()
{
return ("(" + m_cx + "," + m_cy + ")");
}
}
}
illustrates operator overloading
/*
Mastering Visual C# .NET
by Jason Price, Mike Gunderloy
Publisher: Sybex;
ISBN: 0782129110
*/
/*
Example7_12.cs illustrates operator overloading
*/
using System;
// declare the Rectangle class
class Rectangle
{
// declare the fields
public int width;
public int height;
// define constructor
public Rectangle(int width, int height)
{
this.width = width;
this.height = height;
}
// override the ToString() method
public override string ToString()
{
return "width = " + width + ", height = " + height;
}
// overload the == operator
public static bool operator ==(Rectangle lhs, Rectangle rhs)
{
Console.WriteLine("In operator ==");
if (lhs.width == rhs.width && lhs.height == rhs.height)
{
return true;
}
else
{
return false;
}
}
// overload the != operator
public static bool operator !=(Rectangle lhs, Rectangle rhs)
{
Console.WriteLine("In operator !=");
return !(lhs==rhs);
}
// override the Equals() method
public override bool Equals(object obj)
{
Console.WriteLine("In Equals()");
if (!(obj is Rectangle))
{
return false;
}
else
{
return this == (Rectangle) obj;
}
}
// overload the + operator
public static Rectangle operator +(Rectangle lhs, Rectangle rhs)
{
Console.WriteLine("In operator +");
return new Rectangle(lhs.width + rhs.width, lhs.height + rhs.height);
}
}
public class Example7_12
{
public static void Main()
{
// create Rectangle objects
Rectangle myRectangle = new Rectangle(1, 4);
Console.WriteLine("myRectangle: " + myRectangle);
Rectangle myRectangle2 = new Rectangle(1, 4);
Console.WriteLine("myRectangle2: " + myRectangle2);
if (myRectangle == myRectangle2)
{
Console.WriteLine("myRectangle is equal to myRectangle2");
}
else
{
Console.WriteLine("myRectangle is not equal to myRectangle2");
}
Rectangle myRectangle3 = myRectangle + myRectangle2;
Console.WriteLine("myRectangle3: " + myRectangle3);
}
}
A better way to overload !, | and & for ThreeD. This version automatically enables the && and || operators
/*
C#: The Complete Reference
by Herbert Schildt
Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/
/* A better way to overload !, |, and & for ThreeD.
This version automatically enables the && and || operators. */
using System;
// A three-dimensional coordinate class.
class ThreeD {
int x, y, z; // 3-D coordinates
public ThreeD() { x = y = z = 0; }
public ThreeD(int i, int j, int k) { x = i; y = j; z = k; }
// Overload | for short-circuit evaluation.
public static ThreeD operator |(ThreeD op1, ThreeD op2)
{
if( ((op1.x != 0) || (op1.y != 0) || (op1.z != 0)) |
((op2.x != 0) || (op2.y != 0) || (op2.z != 0)) )
return new ThreeD(1, 1, 1);
else
return new ThreeD(0, 0, 0);
}
// Overload & for short-circuit evaluation.
public static ThreeD operator &(ThreeD op1, ThreeD op2)
{
if( ((op1.x != 0) && (op1.y != 0) && (op1.z != 0)) &
((op2.x != 0) && (op2.y != 0) && (op2.z != 0)) )
return new ThreeD(1, 1, 1);
else
return new ThreeD(0, 0, 0);
}
// Overload !.
public static bool operator !(ThreeD op)
{
if(op) return false;
else return true;
}
// Overload true.
public static bool operator true(ThreeD op) {
if((op.x != 0) || (op.y != 0) || (op.z != 0))
return true; // at least one coordinate is non-zero
else
return false;
}
// Overload false.
public static bool operator false(ThreeD op) {
if((op.x == 0) && (op.y == 0) && (op.z == 0))
return true; // all coordinates are zero
else
return false;
}
// Show X, Y, Z coordinates.
public void show()
{
Console.WriteLine(x + ", " + y + ", " + z);
}
}
public class TrueFalseDemo1 {
public static void Main() {
ThreeD a = new ThreeD(5, 6, 7);
ThreeD b = new ThreeD(10, 10, 10);
ThreeD c = new ThreeD(0, 0, 0);
Console.Write("Here is a: ");
a.show();
Console.Write("Here is b: ");
b.show();
Console.Write("Here is c: ");
c.show();
Console.WriteLine();
if(a) Console.WriteLine("a is true.");
if(b) Console.WriteLine("b is true.");
if(c) Console.WriteLine("c is true.");
if(!a) Console.WriteLine("a is false.");
if(!b) Console.WriteLine("b is false.");
if(!c) Console.WriteLine("c is false.");
Console.WriteLine();
Console.WriteLine("Use & and |");
if(a & b) Console.WriteLine("a & b is true.");
else Console.WriteLine("a & b is false.");
if(a & c) Console.WriteLine("a & c is true.");
else Console.WriteLine("a & c is false.");
if(a | b) Console.WriteLine("a | b is true.");
else Console.WriteLine("a | b is false.");
if(a | c) Console.WriteLine("a | c is true.");
else Console.WriteLine("a | c is false.");
Console.WriteLine();
// now use short-circuit ops
Console.WriteLine("Use short-circuit && and ||");
if(a && b) Console.WriteLine("a && b is true.");
else Console.WriteLine("a && b is false.");
if(a && c) Console.WriteLine("a && c is true.");
else Console.WriteLine("a && c is false.");
if(a || b) Console.WriteLine("a || b is true.");
else Console.WriteLine("a || b is false.");
if(a || c) Console.WriteLine("a || c is true.");
else Console.WriteLine("a || c is false.");
}
}
Overload true and fase for ThreeD
/*
C#: The Complete Reference
by Herbert Schildt
Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/
// Overload true and fase for ThreeD.
using System;
// A three-dimensional coordinate class.
class ThreeD {
int x, y, z; // 3-D coordinates
public ThreeD() { x = y = z = 0; }
public ThreeD(int i, int j, int k) { x = i; y = j; z = k; }
// Overload true.
public static bool operator true(ThreeD op) {
if((op.x != 0) || (op.y != 0) || (op.z != 0))
return true; // at least one coordinate is non-zero
else
return false;
}
// Overload false.
public static bool operator false(ThreeD op) {
if((op.x == 0) && (op.y == 0) && (op.z == 0))
return true; // all coordinates are zero
else
return false;
}
// Overload unary --.
public static ThreeD operator --(ThreeD op)
{
// for ++, modify argument
op.x--;
op.y--;
op.z--;
return op;
}
// Show X, Y, Z coordinates.
public void show()
{
Console.WriteLine(x + ", " + y + ", " + z);
}
}
public class TrueFalseDemo {
public static void Main() {
ThreeD a = new ThreeD(5, 6, 7);
ThreeD b = new ThreeD(10, 10, 10);
ThreeD c = new ThreeD(0, 0, 0);
Console.Write("Here is a: ");
a.show();
Console.Write("Here is b: ");
b.show();
Console.Write("Here is c: ");
c.show();
Console.WriteLine();
if(a) Console.WriteLine("a is true.");
else Console.WriteLine("a is false.");
if(b) Console.WriteLine("b is true.");
else Console.WriteLine("b is false.");
if(c) Console.WriteLine("c is true.");
else Console.WriteLine("c is false.");
Console.WriteLine();
Console.WriteLine("Control a loop using a ThreeD object.");
do {
b.show();
b--;
} while(b);
}
}