Introduction to Programming Lecture 44

Class Matrix class Matrix { private : int numRows , numCols ; double ** elements ; } ;

Class Matrix class Matrix { private : int numRows , numCols ; double ** elements ; public : Matrix ( int = 0 , int = 0 ) ; // Default constructor Matrix ( const Matrix & ) ; // Copy constructor ~ Matrix ( ) ; // Destructor

Class Matrix // Utility functions of Matrix class int getRows ( void ) const ; int getCols ( void ) const ; // Input output functions for Matrix class const Matrix & input ( istream & is = cin ) ; const Matrix & input ( ifstream & is ) ; void output ( ostream & os = cout ) const ; void output ( ofstream & os ) const ;

Class Matrix // Plus Operator Matrix operator + ( Matrix & m ) const ; Matrix operator + ( double d ) const ;

d is a variable of type double ‘A’ is an object of a class Matrix A + d ;

d is a variable of type double ‘a’ is an object of a class Matrix d + A ;

Class Matrix // Plus Operator Matrix operator + ( Matrix & m ) const ; Matrix operator + ( double d ) const ; friend Matrix operator + ( double d , Matrix & m ) ; const Matrix & operator += ( Matrix & m ) ;

i += 3 ; i = i + 3 ; A += B ; // A and B are Matrices

Where A and B are both matrices A – B Where A and B are both matrices

d is a variable of type double ‘A’ is an object of a class Matrix A – d ;

d is a variable of type double ‘a’ is an object of a class Matrix d – A ;

Class Matrix // Minus Operator Matrix operator - ( Matrix & m ) const ; Matrix operator - ( double d ) const ; friend Matrix operator - ( double d , Matrix & m ) ;

A * B ; Where A and B are both matrices

d is a variable of type double ‘A’ is an object of a class Matrix A * d ;

d is a variable of type double ‘a’ is an object of a class Matrix d * A ;

Class Matrix // Multiplication Operator Matrix operator * ( const Matrix & m ) ; Matrix operator * ( double d ) const ; friend Matrix operator * ( const double d , const Matrix & m ) ;

‘A’ is an object of a class Matrix d is a variable of type double A / d ;

Class Matrix // Division Operator Matrix operator / ( const double d ) ;

Example // Where m is a matrix // Stream Insertion and Extraction Operator cin >> m ; // Where m is a matrix

Class Matrix // Stream Insertion and Extraction Operator friend istream & operator >> ( istream & , Matrix & ) ; friend ifstream & operator >> ( ifstream & , Matrix & ) ; friend istream & operator << ( istream & , Matrix & ) ; friend ifstream & operator << ( ifstream & , Matrix & ) ;

Class Matrix const Matrix & operator = ( const Matrix & m ) ; const Matrix & transpose ( void ) ;

Class Matrix Matrix :: Matrix ( int row , int col ) // Default Constructor { numRows = row ; numCols = col ; elements = new ( double * ) [ numRows ] ; for ( int i = 0 ; i < numRows ; i ++ ) elements [ i ] = new double [ numCols ] ; for ( int j = 0 ; j < numCols ; j ++ ) elements [ i ] [ j ] = 0.0 ; }

Matrix A ( B ) ;

Matrix A = B ;

Class Matrix Matrix :: Matrix ( const Matrix & m ) { numRows = m.numRows ; numCols = m.numCols ; elements = new ( double * ) [ numRows ] ; for ( int i = 0 ; i < numRows ; i ++ ) elements [ i ] = new double [ numCols ] ; for ( int j = 0 ; j < numCols ; j ++ ) elements [ i ] [ j ] = m.elements [ i ] [ j ] ; }

Class Matrix Matrix :: ~ Matrix ( void ) { delete [ ] elements ; }

Class Matrix int Matrix :: getRows ( ) const { return numRows ; } int Matrix :: getCols ( ) const return numCols ;

Class Matrix void Matrix :: output ( ostream & os ) const { // Print first row with special characters os.setf ( ios :: showpoint ) ; os.setf ( ios :: fixed , ios :: floatfield ) ; os << ( char ) 218 ; for ( int j = 0 ; j < numCols ; j ++ ) os << setw ( 10 ) << " “ ; os << ( char ) 191 << "\n" ;

Class Matrix // Print remaining rows with vertical bars only for ( int i = 0 ; i < numRows ; i ++ ) { os << ( char ) 179 ; for ( int j = 0 ; j < numCols ; j ++ ) os << setw ( 10 ) << setprecision ( 2 ) << elements [ i ] [ j ] ; os << ( char ) 179 << "\n" ; }

Class Matrix // Print last row with special characters os << ( char ) 192 ; for ( int j = 0 ; j < numCols ; j ++ ) os << setw ( 10 ) << " " ; os << ( char ) 217 << "\n" ; }

Class Matrix void Matrix :: output ( ofstream & os ) const { os.setf ( ios :: showpoint ) ; os.setf ( ios :: fixed , ios :: floatfield ) ; os << numRows << " " << numCols << "\n" ; for ( int i = 0 ; i < numRows ; i ++ ) for ( int j = 0 ; j < numCols ; j ++ ) os << setw ( 6 ) << setprecision ( 2 ) << elements [ i ] [ j ] ; os << "\n" ; }

Class Matrix const Matrix & Matrix :: input ( istream & is ) { cout << "Input Matrix size: " << numRows << " rows by " << numCols << " columns \n" ; for ( int i = 0 ; i < numRows ; i ++ ) cout << "Please enter " << numCols << " values separated by spaces for row no." << i+1 << ": " ; for ( int j = 0 ; j < numCols ; j ++ ) cin >> elements [ i ] [ j ] ; } return * this ;

Class Matrix const Matrix & Matrix :: input ( ifstream & is ) { int Rows , Cols ; is >> Rows ; is >> Cols ; if ( Rows > 0 && Cols > 0 ) Matrix temp ( Rows , Cols ) ; * this = temp ; for ( int i = 0 ; i < numRows ; i ++ ) for ( int j = 0 ; j < numCols ; j ++ ) is >> elements [ i ] [ j ] ; } return * this ;

Class Matrix const Matrix & Matrix :: transpose ( ) { if ( numRows == numCols ) // Square Matrix double temp ; for ( int i = 0 ; i < numRows ; i ++ ) for ( int j = i + 1 ; j < numCols ; j ++ ) temp = elements [ i ] [ j ]; elements [ i ] [ j ] = elements [ j ] [ i ] ; elements [ j ] [ i ] = temp ; }

Class Matrix else { Matrix temp(numCols, numRows); for ( int i = 0 ; i < numRows ; i ++ ) for ( int j = 0 ; j < numCols ; j ++ ) temp.elements [ j ] [ i ] = elements [ i ] [ j ] ; } * this = temp ; return * this ;