C++ > Data Structures and Algorithm Analysis in C++ sample source codes

 Fig10_38.cpp - Simple matrix multiplication algorithm with a test program

Fig10_38.cpp - Simple matrix multiplication algorithm with a test program #include <iostream.h> #include "matrix.h" /* START: Fig10_38.txt */ /** * Standard matrix multiplication. * Arrays start at 0. * Assumes a and b are square. */ matrix<int> operator*( const matrix<int> & a, const matrix<int> & b ) { int n = a.numrows( ); matrix<int> c( n, n ); int i; for( i = 0; i < n; i++ ) // Initialization for( int j = 0; j < n; j++ ) c[ i ][ j ] = 0; for( i = 0; i < n; i++ ) for( int j = 0; j < n; j++ ) for( int k = 0; k < n; k++ ) c[ i ][ j ] += a[ i ][ k ] * b[ k ][ j ]; return c; } /* END */ int main( ) { matrix<int> a( 2, 2 ); a[ 0 ][ 0 ] = 1; a[ 0 ][ 1 ] = 2; a[ 1 ][ 0 ] = 3; a[ 1 ][ 1 ] = 4; matrix<int> c = a * a; cout << c[ 0 ][ 0 ] << " " << c[ 0 ][ 1 ] << endl << c[ 1 ][ 0 ] << " " << c[ 1 ][ 1 ] << endl; return 0; }



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