Ch 8. Operator Overloading, Friends, and Referencescontents.kocw.net/KOCW/document/2013/youngnam/YoungTak...Operator Overloading Introduction Operators +, -, %, ==, etc. Really just

Ch 8. Operator Overloading, Friends, and References

2013-2 O-O Programming & Data Structure

September 4, 2013

Prof. Young-Tak Kim Advanced Networking Technology Lab. (YU-ANTL)

Dept. of Information & Comm. Eng, Graduate School, Yeungnam University, KOREA

(Tel : +82-53-810-2497; Fax : +82-53-810-4742 http://antl.yu.ac.kr/; E-mail : [email protected])

http://antl.yu.ac.kr/

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL)

O-O Programming & Data Structure Prof. Young-Tak Kim ch 8 - 2

Outline

Basic Operator Overloading Unary operators: ++, -- Binary operators: +, -, *, /, %, ==, != As member functions

Friends and Automatic Type Conversion Friend functions, friend classes Constructors for automatic type conversion

References and More Overloading << and >> Operators: = , [], ++, --



Operator Overloading Introduction Operators +, -, %, ==, etc. Really just functions!

Simply "called" with different syntax: x + 7 "+" is binary operator with x and 7 as operands We "like" this notation as humans

Think of it as: +(x, 7) "+" is the function name x, 7 are the arguments Function "+" returns "sum" of it’s arguments



Operator Overloading Perspective Built-in operators e.g., +, -, = , %, ==, /, * Already work for C++ built-in types In standard "binary" notation

We can overload them! To work with OUR types! To add "Chair types", or "Money types" As appropriate for our needs In "notation" we’re comfortable with

Always overload with “similar actions"!



Why Operator Overloading is necessary ?

Concise expression and easy to understand using the usual mathematical operators, concise notations are

possible /* What you have use */

double mA[N][N], mB[N][N], mC[N][N], mD[N][N], mE[N][N], mF[N][N]; getMtrx(mA, N); getMtrx(mB, N); mtrxAdd(mA, mB, mC, N); mtrxSubtract(mA, mB, mD, N); mtrxMultiply(mA, mB, mE, N); mtrxInverse(mA, mF, N);

/* What can be possible with */ // Class definition for Mtrx Mtrx mA, mB, mC, mD, mE, mInv; cin >> mA; cin >> mB; mC = mA + mB; mD = mA - mB; mE = mA * mB; mInv = ~mA;



Overloading Basics

Overloading operators VERY similar to overloading functions Operator itself is "name" of function

Example Declaration: const Money operator +( const Money& amount1, const Money& amount2);

Overloads + for operands of type Money Uses constant reference parameters for efficiency Returned value is type Money Allows addition of "Money" objects



Implementation of operator overloading

Two approaches case 1: implementation as non-member function similar to usual function overloading standalone function operator overloading is not included in class definition generally simple to implement

case 2: implementation as a member function operator overloading is included in class definition principles suggest member operators, to maintain the “sprit” of object-

oriented programming



Overloaded "+"

Given previous example: Note: overloaded "+" NOT member function Definition is "more involved" than simple "add" Requires issues of money type addition Must handle negative/positive values

Operator overload definitions generally very simple Just perform "addition" particular to "your" type



Money "+" Definition Definition of "+" operator for Money class:



Overloaded "=="

Equality operator, == Enables comparison of Money objects Declaration:

bool operator ==(const Money& amount1, const Money& amount2); Returns bool type for true/false equality

Again, it’s a non-member function (like "+" overload)



Overloaded "==" for Money Definition of "==" operator for Money

class:



Constructors Returning Objects

Constructor a "void" function? We "think" that way, but no A "special" function With special properties CAN return a value!

Recall return statement in "+" overload for Money type: return Money(finalDollars, finalCents); Returns an "invocation" of Money class! So constructor actually "returns" an object! Called an "anonymous object"



Returning by const Value

Consider "+" operator overload again: const Money operator +(const Money& amount1, const Money& amount2); Returns a "constant object"? Why?

Consider impact of returning "non-const" object to see…



Returning by non-const Value

Consider "no const" in declaration: Money operator +(const Money& amount1, const Money& amount2);

Consider expression that calls: m1 + m2 Where m1 & m2 are Money objects Object returned is Money object We can "do things" with objects! Like call member functions…



What to do with Non-const Object

Can call member functions: We could invoke member functions on

object returned by expression m1+m2: (m1+m2).output(); //Legal, right?

– Not a problem: doesn’t change anything

(m1+m2).input(); //Legal! – PROBLEM! //Legal, but MODIFIES! Allows modification of "anonymous" object! Can’t allow that here!

So we define the return object as const



Overloading Unary Operators

C++ has unary operators: Defined as taking one operand e.g., - (negation) x = -y; // Sets x equal to negative of y

Other unary operators: ++ (increment), -- (decrement)

Unary operators can also be overloaded



Overload "-" for Money

Overloaded "-" function declaration Placed outside class definition:

const Money operator –(const Money& amount); Notice: only one argument Since only 1 operand (unary)

"-" operator is overloaded twice! For two operands/arguments (binary) For one operand/argument (unary) Definitions must exist for both



Overloaded "-" Definition

Overloaded "-" unary function definition: const Money operator –(const Money& amount) { return Money(-amount.getDollars(), -amount.getCents()); }

Applies "-" unary operator to built-in type Operation is "known" for built-in types

Returns anonymous object again



Overloaded "-" Usage

Consider: Money amount1(10), amount2(6), amount3; amount3 = amount1 – amount2; Calls binary "-" overload

amount3.output(); //Displays $4.00 amount3 = -amount1; Calls unary "-" overload

amount3.output(); //Displays -$10.00



Overloading as Member Functions Previous examples: standalone functions Defined outside a class

Can overload as "member operator" Considered "member function" like others

When operator is member function: Only ONE parameter, not two! Calling object serves as 1st parameter



Member Operator in Action

Money cost(1, 50), tax(0, 15), total; total = cost + tax; If "+" overloaded as member operator: Variable/object cost is calling object Object tax is single argument

Think of as: total = cost+(tax);

Declaration of "+" in class definition: const Money operator+(const Money& amount); Notice only ONE argument



Example Cmplx (1)

/** * Cmplx.h */ #include <iostream> using namespace std; class Cmplx { friend ostream & operator<< (ostream &, const Cmplx &); friend istream & operator>> (istream &, Cmplx &); public: Cmplx(double real=0.0, double imagin=0.0); // constructor const Cmplx operator+(const Cmplx &); const Cmplx operator-(const Cmplx &); private: double real; double imagin; };



Example Cmplx (2) /** * Cmplx.cpp */ #include <iostream> #include "Cmplx.h" using namespace std; Cmplx::Cmplx(double r, double i) :real(r), imagin(i) { } ostream &operator<<(ostream &output, const Cmplx &c) { output << "Complex (" << c.real << ", " << c.imagin << ")" << endl; return output; } istream &operator>>(istream &input, Cmplx &c) { input >> c.real; input >> c.imagin; return input; }



Example Cmplx (3)

/* Cmplx.cpp (cont.) */ const Cmplx Cmplx::operator+(const Cmplx &c) { Cmplx result; result.real = real + c.real; result.imagin = imagin + c.imagin; return result; } const Cmplx Cmplx::operator-(const Cmplx &c) { Cmplx result; result.real = real - c.real; result.imagin = imagin - c.imagin; return result; }



Example Cmplx (4) /**

* main.cpp */ #include <iostream> #include "Cmplx.h" using namespace std; void main() { Cmplx c1, c2, c3, c4; cout << "input c1.real and c1.imagin: "; cin >> c1; cout << "c1 : " << c1 << endl; cout << "input c2.real and c2.imagin: "; cin >> c2; cout << "c2 : " << c2 << endl; c3 = c1 + c2; cout << "c3 = c1 + c2: " << c3 << endl; c4 = c1 - c2; cout << "c4 = c1 - c2: " << c4 << endl; }

<Result of Execution>



const Functions

When to make function const? Constant functions not allowed to alter class

member data Constant objects can ONLY call constant

member functions

Good style dictates: Any member function that will NOT modify data

should be made const

Use keyword const after function declaration and heading



Overloading Operators: Which Method?

Object-Oriented-Programming Principles suggest member operators Many agree, to maintain "spirit" of OOP

Member operators more efficient No need to call accessor (e.g., get()) and mutator (e.g., set())

functions



Overloading Function Application () Function call operator, ( ) Must be overloaded as member function Allows use of class object like a function Can overload for all possible numbers of arguments

Example: Aclass anObject; anObject(42); If ( ) overloaded calls overload



Other Overloads

&&, ||, and comma (‘,’) operator Predefined versions work for bool types Recall: use "short-circuit evaluation" When overloaded no longer uses short-circuit Uses "complete evaluation" instead Contrary to expectations

Generally should not overload these operators



Friend Functions

Nonmember functions Recall: operator overloads as nonmembers They access data through accessor and mutator functions Very inefficient (overhead of calls)

Friends can directly access private class data No overhead, more efficient

So: best to make nonmember operator overloads friends!



Friend Functions

Friend function of a class Not a member function Has direct access to private members Just as member functions do

Use keyword friend in front of function declaration Specified IN class definition But they’re NOT member functions!



Friend Function Uses

Operator Overloads Most common use of friends Improves efficiency Avoids need to call accessor/mutator member functions Operator must have access anyway Might as well give full access as friend

Friends can be any function



Example of friend function (1)

/** * Cmplx.h */ #include <iostream> using namespace std; class Cmplx { friend ostream & operator<< (ostream &, const Cmplx &); friend istream & operator>> (istream &, Cmplx &); public: Cmplx(double real=0.0, double imagin=0.0); // constructor const Cmplx operator+(const Cmplx &); const Cmplx operator-(const Cmplx &); private: double real; double imagin; };



Example of friend function (2) /* Cmplx.cpp */ ostream &operator<<(ostream &output, const Cmplx &c) { output << "Complex (" << c.real << ", " << c.imagin << ")" << endl; return output; } istream &operator>>(istream &input, Cmplx &c) { input >> c.real; input >> c.imagin; return input; }

/** main.cpp */ . . . . Cmplx c1, c2, c3, c4; cout << " input c1.real and c1.imagin: "; cin >> c1; cout << " c1 : " << c1 << endl; cout << " input c2.real and c2.imagin: "; cin >> c2; cout << " c2 : " << c2 << endl; . . . .



Friend Function Purity

Friends not pure? "Spirit" of OOP dictates all operators and functions be

member functions Many believe friends violate basic OOP principles

Advantageous? For operators: very! Allows automatic type conversion Still encapsulates: friend is in class definition Improves efficiency



Friend Classes

Entire classes can be friends Similar to function being friend to class Example:

class F is friend of class C All class F member functions are friends of C NOT reciprocated Friendship granted, not taken

Syntax: friend class F Goes inside class definition of "authorizing" class



References

Reference defined: Name of a storage location Similar to "pointer"

Example of stand alone reference: int robert;

int& bob = robert; bob is reference to storage location for robert Changes made to bob will affect robert

Confusing?



Comparisons of call-by-{value, reference, pointer}

Call-by-Value

/* Call-by-Value */ int function( int x ) { int y; y = x * x + 2; return y; } void main() { int j, k; . . . . k = function ( j ); }

Call-by-Reference

/* Call-by-Reference */ int function( int& x ) { int y; y = x * x + 2; return y; } void main() { int j, k; . . . . k = function ( j ); }

Call-by-Pointer

/* Call-by-Reference */ int function( int* px ) { int y; y = (*px) * (*px) + 2; retrun y; } void main() { int j, k; . . . . k = function ( &j ); }



References Usage

Seemingly dangerous

Useful in several cases:

Call-by-reference Often used to implement this mechanism

Returning a reference Allows operator overload implementations to

be written more naturally Think of as returning an "alias" to a variable



Returning Reference

Syntax: double& sampleFunction(double& variable); double& and double are different Must match in function declaration and heading

Returned item must "have" a reference Like a variable of that type Cannot be expression like "x+5" Has no place in memory to "refer to"



Returning Reference in Definition

Example function definition: double& sampleFunction(double& variable) { return variable; }

Trivial, useless example Shows concept only Major use: Certain overloaded operators, such as extraction operator (>>)

and insertion operator (<<)



Overloading >> and <<

Enables input and output of our objects Similar to other operator overloads New subtleties

Improves readability Like all operator overloads do Enables:

cout << myObject; cin >> myObject;

Instead of need for: myObject.output(); myObject.input(); …



Overloading <<

Insertion operator, << Used with cout A binary operator

Example: cout << "Hello"; Operator is << 1st operand is predefined object cout From library iostream

2nd operand is literal string "Hello"



Overloading <<

Operands of << Cout object, of class type ostream Our class type

Recall Money class Used member function output() Nicer if we can use << operator:

Money amount(100); cout << "I have " << amount << endl;

instead of: cout << "I have "; amount.output()



Overloaded << Return Value

Money amount(100); cout << amount; << should return some value To allow cascades:

cout << "I have " << amount; (cout << "I have ") << amount; Two are equivalent

What to return? cout object! Returns its first argument type, ostream



Overloaded << and >> Example:

Display 8.5 Overloading << and >> (1 of 5)















Assignment Operator, =

Must be overloaded as member operator Automatically overloaded Default assignment operator: Member-wise copy Member variables from one object

corresponding member variables from other

Default OK for simple classes But class with pointers and dynamic memory allocation must write our own assignment operator= overloading!



Example of “operator=” overloading (1) /** Date.h */ #include <iostream> using namespace std; class DateArray; class Date { friend class DateArray; friend istream &operator>>(istream &, Date &); friend ostream &operator<<(ostream &, const Date &); public: Date(); Date(int y, int m, int d); const Date operator+(int dd); const Date operator-(int dd); const Date operator++(); // prefix const Date operator++(int dummy); // postfix const Date operator--(); // prefix const Date operator--(int dummy); // postfix const Date operator=(const Date rightSide); private: int year; int month; int day; };



Example of “operator=” overloading (2)

const Date Date::operator=(const Date rightSide) { year = rightSide.year; if (rightSide.month >=1 && rightSide.month <=12) { month = rightSide.month; } else { cout << "Error in month assignment : " << rightSide.month << endl; month = 1; } if (rightSide.day >= 1 && rightSide.day <= daysPerMonth[month]) { day = rightSide.day; } else { cout << "Error in day assignment : " << rightSide.day; cout << " ( month: " << rightSide.month << ")" << endl; day = 1; } return *this; }



Increment and Decrement

Each operator has two versions Prefix notation: ++x; y = ++x; same as x = x+1; y = x;

Postfix notation: x++; y = x++; same as y = x; x = x+1

Must distinguish in overload Standard overload method Prefix int operator++();

Add 2d parameter of type int Postfix int operator++(int ignore); Just a marker for compiler! Specifies postfix is allowed



Display 8.6 (1)

#include <iostream> #include <cstdlib> using namespace std; class IntPair { public: IntPair(int firstValue, int secondValue); IntPair operator++( ); //Prefix version IntPair operator++(int); //Postfix version void setFirst(int newValue); void setSecond(int newValue); int getFirst( ) const; int getSecond( ) const; private: int first; int second; };



Display 8.6 (2)

int main( ) { IntPair a(1,2); cout << "Postfix a++: Start value of object a: "; cout << a.getFirst( ) << " " << a.getSecond( ) << endl; IntPair b = a++; cout << "Value returned: "; cout << b.getFirst( ) << " " << b.getSecond( ) << endl; cout << "Changed object: "; cout << a.getFirst( ) << " " << a.getSecond( ) << endl; a = IntPair(1, 2); cout << "Prefix ++a: Start value of object a: "; cout << a.getFirst( ) << " " << a.getSecond( ) << endl; IntPair c = ++a; cout << "Value returned: "; cout << c.getFirst( ) << " " << c.getSecond( ) << endl; cout << "Changed object: "; cout << a.getFirst( ) << " " << a.getSecond( ) << endl; return 0; }



Display 8.6 (3)

IntPair::IntPair(int firstValue, int secondValue) : first(firstValue), second(secondValue) {/*Body intentionally empty*/} IntPair IntPair::operator++(int ignoreMe) //postfix version { int temp1 = first; int temp2 = second; first++; second++; return IntPair(temp1, temp2); } IntPair IntPair::operator++( ) //prefix version { first++; second++; return IntPair(first, second); }



Display 8.6 (4)

Result of execution see Page 381

void IntPair::setFirst(int newValue) { first = newValue; } void IntPair::setSecond(int newValue) { second = newValue; } int IntPair::getFirst( ) const { return first; } int IntPair::getSecond( ) const { return second; }



Overload Indexed Array Operator, [ ]

Can overload [ ] for your class To be used with objects of your class

Operator must return a reference!

operator[] must be a member function!



Example : CmplxArray (1) /** Cmplx.h */ #ifndef CMPLX_H #define CMPLX_H #include <iostream> using namespace std; class CmplxArray; class Cmplx { friend ostream & operator<< (ostream &, const Cmplx &); friend istream & operator>> (istream &, Cmplx &); friend class CmplxArray; public: Cmplx(double real=0.0, double imagin=0.0); // constructor const Cmplx operator+(const Cmplx &); const Cmplx operator-(const Cmplx &); void setReal(double r); void setImagin(double im); private: double real; double imagin; }; #endif



Example : CmplxArray (2) /** CmplxArray.h */

#ifndef CMPLXARRAY_H #define CMPLXARRAY_H #include <iostream> #include "Cmplx.h" using namespace std; class CmplxArray { public: CmplxArray(int size); // constructor CmplxArray(const CmplxArray &obj); ~CmplxArray(); int size() { return cmplxArrySize; } Cmplx &operator[](int sub); private: Cmplx *pCA; int cmplxArrySize; void subError(); // out of subscript range }; #endif



Example : CmplxArray (3) /** Cmplx.cpp */

#include <iostream> #include "Cmplx.h" using namespace std; Cmplx::Cmplx(double r, double i) :real(r), imagin(i) { } ostream &operator<<(ostream &output, const Cmplx &c) { output << "Complex (" << c.real << ", " << c.imagin << ")" << endl; return output; } istream &operator>>(istream &input, Cmplx &c) { input >> c.real; input >> c.imagin; return input; }



Example : CmplxArray (4) void Cmplx::setReal(double r)

{ real = r; } void Cmplx::setImagin(double im) { imagin = im; } const Cmplx Cmplx::operator+(const Cmplx &c) { Cmplx result; result.real = real + c.real; result.imagin = imagin + c.imagin; return result; } const Cmplx Cmplx::operator-(const Cmplx &c) { Cmplx result; result.real = real - c.real; result.imagin = imagin - c.imagin; return result; }



Example : CmplxArray (5) /** CmplxArray.cpp */

#include "CmplxArray.h" #include "Cmplx.h" CmplxArray::CmplxArray(int size) // constructor { cmplxArrySize = size; pCA = new Cmplx[size]; for (int i=0; i<size; i++) { pCA[i].real = 0.0; pCA[i].imagin = 0.0; } } CmplxArray::CmplxArray(const CmplxArray &obj) // constructor { cmplxArrySize = obj.cmplxArrySize; pCA = new Cmplx[cmplxArrySize]; for (int i=0; i<cmplxArrySize; i++) { pCA[i] = obj.pCA[i]; // *(pCA+i) = obj.pCA[i]; } } CmplxArray::~CmplxArray() // destructor { if (cmplxArrySize > 0) delete [] pCA; }



Example : CmplxArray (6)

void CmplxArray::subError() { cout << "ERROR: Subscript out of range.\ n"; exit(0); } Cmplx &CmplxArray::operator [](int sub) { if (sub < 0 || sub >= cmplxArrySize) // checking validity of range subError(); return pCA[sub]; }



Example : CmplxArray (7) #include <iostream>

#include "CmplxArray.h" #include "Cmplx.h" using namespace std; void main() { CmplxArray CMPLXES(4); cout << "\ n Input real and imagin in double type: "; cin >> CMPLXES[0]; cout << " CMPLXES[0] : " << CMPLXES[0] << endl; cout << " Input real and imagin in double type: "; cin >> CMPLXES[1]; cout << " CMPLXES[1] : " << CMPLXES[1] << endl; CMPLXES[2] = CMPLXES[0] + CMPLXES[1]; CMPLXES[3] = CMPLXES[0] - CMPLXES[1]; cout << " CMPLXES[2] : " << CMPLXES[2] << endl; cout << " CMPLXES[3] : " << CMPLXES[3] << endl; }



Summary 8-1

C++ built-in operators can be overloaded To work with objects of your class

Operators are really just functions

Friend functions have direct private member access

Operators can be overloaded as member functions 1st operand is calling object



Summary 8-2

Friend functions add efficiency only Not required if sufficient accessors/mutators

available

Reference "names" a variable with an alias

Can overload <<, >> Return type is a reference to stream type



Homework 8

8.1 Programming projects 8-1. (operator overloading for Class Money)

8.2 Programming projects 8-3. (operator overloading for complex number)

8.3 Operator overloading for Class Mtrx 1)Define a class Mtrx that contains a private data member of 2-dimentional array to

store double data type. Class Mtrx has operator overloading of input/output operator (>>, <<), arithmetic operator (+, -, *), equality operator (==, !=), assignment operator (=).

2)Define a class MtrxArray, that include a given number of Mtrx instances. The MtrxArray should provide operator overloading of [].

3) In main() function, specify 6 instances of 7x7 Mtrx array as mtrx[0..5]. 4) Using 2 two dimensional arrays in the main() function, initialize the first two arrays. 5) Using the mtrx[0] and mtrx[1], perform arithmetic operations (+, -, *), and store

the results at mtrx[2], mtrx[3], and mtrx[4], respectively. 6) Using the mtrx[0] and mtrx[1], perform operators == and !=, print out the results. 7) Output the calculated result of mtrx[] using operator <<. (Note. Header file and main() function should include following sample source code.)



8.3 (cont) Header File (“Mtrx.h”)

/** Class_Mtrx.h */ #ifndef CLASS_MTRX_H #define CLASS_MTRX_H using namespace std; class Mtrx { friend ostream & operator<< (ostream &, const Mtrx &); friend istream & operator>> (istream &, Mtrx &); public: Mtrx(); Mtrx(int mSize); void init(double dA[], int num_data, int mSize); void init(int mSize); void print(); Mtrx add(Mtrx); Mtrx sub(Mtrx); Mtrx multiply(Mtrx);



8.3 (cont) Header File (“Mtrx.h”)

/** Class_Mtrx.h (cont.) */ Mtrx operator+(Mtrx); Mtrx operator-(Mtrx); Mtrx operator*(Mtrx); bool operator==(Mtrx); bool operator!=(Mtrx); const Mtrx operator= (const Mtrx &right); private: int mSize; double **dM; double det; }; #endif



8.3 (cont) Header File (“MtrxArray.h”) /** MtrxArray.h */

#ifndef MTRXARRAY_H #define MTRXARRAY_H #include <iostream> using namespace std; class Mtrx; class MtrxArray { public: MtrxArray(int arraySize, int mtrxSize); Mtrx &operator[](int sub); int getSize(); private: Mtrx *pMtrx; int mtrxArrySize; void subError(); }; #endif



8.3 (cont) main.cpp

/** main.cpp */ #include <iostream> #include "Mtrx.h" #include "MtrxArray.h" #define MTRX_SIZE 7 #define NUM_MTRX 6 using namespace std; int main() { double mA[MTRX_SIZE * MTRX_SIZE] = {1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 2.0, 3.0, 4.0, 5.0, 1.0, 9.0, 3.0, 3.0, 2.0, 5.0, 3.0, 2.0, 3.0, 2.0, 4.0, 3.0, 2.0, 7.0, 2.0, 7.0, 2.0, 5.0, 3.0, 2.0, 7.0, 2.0, 7.0, 2.0, 6.0, 3.0, 2.0, 7.0, 2.0, 1.0, 5.0, 7.0, 4.0, 3.0, 2.0, 9.0, 5.0, 8.0};



8.3 (cont) main.cpp

double mB[MTRX_SIZE * MTRX_SIZE] = {1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0}; MtrxArray mtrx(NUM_MTRX, MTRX_SIZE); mtrx[0].init(mA, MTRX_SIZE * MTRX_SIZE, MTRX_SIZE); mtrx[1].init(mB, MTRX_SIZE * MTRX_SIZE, MTRX_SIZE); cout << "mtrx[0]:\ n" << mtrx[0] << endl; cout << "det of mtrx[0]= " << !mtrx[0] << endl; cout << "mtrx[1]:\ n" << mtrx[1] << endl; mtrx[2] = mtrx[0] + mtrx[1]; cout << "mtrx[2] = mtrx[0] + mtrx[1]: \ n" << mtrx[2];



8.3 (cont) main.cpp

mtrx[3] = mtrx[0] - mtrx[1]; cout << "mtrx[3] = mtrx[0] - mtrx[1]: \ n" << mtrx[3]; mtrx[5] = mtrx[0] * mtrx[4]; cout << "mtrx[5] = mtrx[0] * mtrx[4]: \ n" << mtrx[5]; if (mtrx[0] == mtrx[1]) cout << "mtrx[0] and mtrx[1] are equal.\ n"; if (mtrx[0] != mtrx[1]) cout << "mtrx[0] and mtrx[1] are not equal.\ n"; return 0; }

Documents

Ch 8. Operator Overloading, Friends, and Referencescontents.kocw.net/KOCW/document/2013/youngnam/YoungTak...Operator Overloading Introduction Operators +, -, %, ==, etc. Really just