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MATRIXMULT.CPP
#include <iostream>
#include <vector>
#include <string>
#include <cassert>
#include "Matrix.h"
using namespace std;
int SetRows()
{
int num_rows;
cout << "Input the number of rows of the matrix." << endl;
cin >> num_rows;
return num_rows;
}
int SetCols()
{
int num_cols;
cout << "Input the number of columns of the matrix." << endl;
cin >> num_cols;
cout << "\n";
return num_cols;
}
int SetElements(int num_rows, int num_cols) //Set the number of elements to be the product of the number of rows and columns.
{
int num_elements = num_rows * num_cols;
return num_elements;
}
void New_Matrix(Matrix M) //Request information for a specific matrix.
{
cout << "Enter information for "<< M.m_name << ". \n";
}
void InstantiateMatrix(Matrix& M) //Input numerical values into our matrix.
{
cout << "Now input the values held in " << M.m_name << "." <<endl;
cout << "Input the elements row by row.\n" <<endl;
M.m_matrixElements.reserve(M.m_elements);
for (int h = 0 ; h < M.m_elements ; h++)
{
float element;
cin >> element;
M.m_matrixElements.push_back(element);
}
cout << endl;
}
void MatrixMultiplier(Matrix First, Matrix Second, Matrix &Product) // This is where the multiplication occurs.
{
for( int i = 0; i < First.m_rows ; i++)
for (int j = 0 ; j < Second.m_cols ; j ++)
for (int k = 0; k < Product.m_cols; k++)
Product.m_matrixElements[i*Product.m_cols + j] += First.m_matrixElements[i*First.m_cols+k]*Second.m_matrixElements[j+Second.m_cols*k];
}
int main()
{
cout << "\n\nWelcome to the matrix multiplier!\n" << endl; //Welcome, etc.
cout << "You will be asked to input some information" << endl;
cout << "about the matrices you wish to multiply and" << endl;
cout << "then the computer will make sure the matrice" << endl;
cout << "s are multiplicable. Then you will be return" << endl;
cout << "ed the product!\n" << endl;
Matrix A("Matrix A"), B("Matrix B"), C("Matrix C");
New_Matrix(A);
A.m_rows = SetRows(); // Here we initialize some important data members of matrix A.
A.m_cols = SetCols();
A.m_elements = SetElements(A.m_rows, A.m_cols);
New_Matrix(B);
B.m_rows = SetRows();
B.m_cols = SetCols();
B.m_elements = SetElements(B.m_rows, B.m_cols);
assert ( A.m_cols == B.m_rows); // Make sure the matrices can be multiplied before anything else.
InstantiateMatrix(A); // Here the matrices are filled with numbers.
InstantiateMatrix(B);
C.m_elements = A.m_cols*B.m_rows; //Set dimensions for matrix C, the product matrix, and reserve some memory for it.
C.m_rows = A.m_rows;
C.m_cols = B.m_cols;
C.m_matrixElements.reserve(C.m_elements);
void MatrixMultiplier(A, B, C); // Use the MatrixMultiplier function.
for (int i = 0; i < C.m_elements ; i++) //Here we output the product matrix.
{
cout << C.m_matrixElements[i] << " ";
if (( i + 1)% C.m_cols == 0)
cout << endl;
}
}
MATRIX.H
#ifndef Matrix_Def
#define Matrix_Def
#include <vector>
#include <string>
using namespace std;
class Matrix
{
public:
string m_name; //name the matrix
int m_rows; //give it a number of rows, columns, and elements.
int m_cols;
int m_elements;
vector<float> m_matrixElements; // This is the container for the matrix elements
Matrix(string name); // This is our constructor.
};
#endif
MATRIXSTUFF.CPP
#include <string>
#include "Matrix.h"
using namespace std;
Matrix::Matrix(string name) : m_name(name) {} // Our constructor. Name the matrix.
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