code for reading a file then storing the value and matrix into the system..

[slizorn]

hi, well this is the file i have to read into the system...

<matrix>
    rows = 2
    cols = 2
 
1 2
2 4
</matrix>
 

any ideas on how to do it?

below is my code..
and i checked that this doesnt work...
and apparantly someone told me that this is in c programmin style..
could ya help me design a method to read the file in a c++ programming way?
i have done my work.. and this is just exercise from the textbook i am learning c++ from.. unfortunately it doesnt have the solutions.. so i am lost on how to do it.. check my other postings to see that i have actually done my work and this is not homework.. so could someone help me please????

void Matrix::readMatrixFile(string FILENAME)
{
    const string filename(FILENAME);
    ifstream file(filename.c_str());
    string line;
    if (getline(file, line) && line == "<matrix>")
    {
        if (file >> line /* "rows" */ && file >> line /* "=" */ && file >> row && getline(file,line) /* ; */)
        {
            if (file >> line /* "cols" */ && file >> line /* "=" */ && file >> col && getline(file,line) /* ; */)
            {
                for (int r = 0; r < row; r++)
                {
                    for (int c = 0; c < col; c++)
                    {
                        int value;
                        if (file >> value)
                        {
                            m[r][c] = value;
                        }
                    }
                    cout << endl;
                }
            }
        }
    }
}
 

thanks

[boxfish]

Hi,
Well, the code works fine for me, what goes wrong when you run it?

[gpraghuram]

You are reading a ; from the line rows = 2 but the file you have posted dosent have it...
Also i think the logic is complex....
Try reading the vine and tokenize it to get the data.

Raghu

[weaknessforcats]

You may be going to a lot of extra touble here. All arrays in C++ are one-dimensional. You might read this: http://bytes.com/forum/thread772412.html.

[slizorn]

You are reading a ; from the line rows = 2 but the file you have posted dosent have it...
Also i think the logic is complex....
Try reading the vine and tokenize it to get the data.

Raghu

how to tolkenize it to get the data?
could u show me the code that does it?

[slizorn]

Hi,
Well, the code works fine for me, what goes wrong when you run it?

well the program doesnt work for me when i run it...
could u take a look and tell me wats wrong?

header file...

#pragma once
#include <iostream>
#include <fstream>
#include <string>
#include "Matrix.h"
using namespace std;
 
class Matrix
{
public:
    Matrix(void);
    ~Matrix(void);
    void readMatrixFile(string FILENAME);
    void addMatrix(Matrix m1, Matrix m3);
    void displayMatrix();
    void transposeMatrix();
    void multiplyMatrices(Matrix m2, Matrix m3);
 
private:
    int row;
    int col;
    /*m = new (double*)[10];
    for(int i = 0; i < 10; i++)
    {
        m[i] = new double[10];
    }
    for(int j = 0; j < 10; j++)
    {
        delete[] m[i];
    }
    delete[] m;*/
    double m[10][10];
};
 

matrix.cpp file

#include <iostream>
#include <fstream>
#include <string>
#include "Matrix.h"
using namespace std;
 
 
Matrix::Matrix(void)
{
}
 
 
Matrix::~Matrix(void)
{
}
 
 
void Matrix::readMatrixFile(string FILENAME)
{
    const string filename(FILENAME);
    ifstream file(filename.c_str());
    string line;
    if (getline(file, line) && line == "<matrix>")
    {
        if (file >> line /* "rows" */ && file >> line /* "=" */ && file >> row && getline(file,line) /* ; */)
        {
            if (file >> line /* "cols" */ && file >> line /* "=" */ && file >> col && getline(file,line) /* ; */)
            {
                for (int r = 0; r < row; r++)
                {
                    for (int c = 0; c < col; c++)
                    {
                        int value;
                        if (file >> value)
                        {
                            m[r][c] = value;
                        }
                    }
                    cout << endl;
                }
            }
        }
    }
}
 
 
void Matrix::addMatrix(Matrix m1, Matrix m3)
{
    for(int a = 0; a < row; a++)
    {
        for(int b = 0; b < col; b++)
        {
            m3.m[a][b]=(m1.m[a][b] + m[a][b]);
        }
    }
}
 
 
void Matrix::displayMatrix()
{
    for(int i = 0; i < row; i++)
    {
        cout << "| ";
        for (int j = 0; j < col; j++)
        {
            cout << m[i][j] << " ";
        }
        cout << "|" << endl;
    }
}
 
 
void Matrix::transposeMatrix()
{
    for(int k = 0; k < row; k++)
    {
        for(int j = 0; j < col; j++)
        {
            m[k][j] = m[j][k];
            m[j][k] = m[k][j];
        }
    }
}
 
 
void Matrix::multiplyMatrices(Matrix m2, Matrix m3)
{
    if(col != m2.row)
    {
        cout << "These two matrices cannot be multiplied!!!" << endl;
    }
    else
    {
        for(int i = 0; i < row; i++)
        {
            for(int j = 0; j < m2.col; j++)
            {
                m3.m[i][j] = 0;
                for(int k = 0; k < m2.row; k++)
                {
                    m3.m[i][j] = m3.m[i][j] + m[i][k] * m2.m[k][j];
                }
            }
        }
    }
}
 

cpp file containing main

#include <iostream>
#include <fstream>
#include <string>
#include "Matrix.h"
using namespace std;
 
 
int main(int argc, char* argv[])
{
    Matrix m1, m2 ,m3;
    char theOption = '0';
    char whichMatrixToDisplay;
    string filename1, filename2;
 
    while(theOption != '5')
    {
        cout << "Please choose one of the following options from the menu below:" << endl;
        cout << "---------------------------------------------------------------" << endl;
        cout << "(1) Add two matrices" << endl;
        cout << "(2) Multiply two matrices" << endl;
        cout << "(3) Take transpose of a matrix" << endl;
        cout << "(4) Display a matrix" << endl;
        cout << "(5) Exit" << endl;
        cout << "---------------------------------------------------------------" << endl;
        cin >> theOption;
 
        switch(theOption)
        {
            case '1':
                cout << "You have chosen option 1!: Add two matices!" << endl;
                cout << "Please enter the two filenames that contain the two input matrices respectively!" << endl;
                cout << "Enter name of 1st file" << endl;
                cin >> filename1;
                cout << "Enter name of 2nd file" << endl;
                cin >> filename2;
                m1.readMatrixFile(filename1);
                m2.readMatrixFile(filename2);
                m2.addMatrix(m1, m3);
                cout << "The two matrices have been added together." << endl;
                cout << "Select (4): Display a matrix to view it." << endl << endl;
                break;
 
            case '2':
                cout << "You have chosen option 2!: Multiply two matices!" << endl;
                cout << "Please enter the two filenames that contain the two input matrices respectively!" << endl;
                cout << "Enter name of 1st file" << endl;
                cin >> filename1;
                cout << "Enter name of 2nd file" << endl;
                cin >> filename2;
                m1.readMatrixFile(filename1);
                m2.readMatrixFile(filename2);
                m1.multiplyMatrices(m2, m3);
                cout << "The two matrices have been multiplied with each other." << endl;
                cout << "Select (4): Display a matrix to view it." << endl << endl;
                break;
 
            case '3':
                cout << "You have chosen option 3!: Transpose a matrix!" << endl;
                cout << "Please enter the filename that contains the matrix to be transposed!" << endl;
                cout << "Enter name of file" << endl;
                cin >> filename1;
                m1.readMatrixFile(filename1);
                m1.transposeMatrix();
                cout << "The matrix has been transposed." << endl;
                cout << "Select (4): Display a matrix to view it." << endl << endl;
                break;
 
            case '4':
                cout << "You have chosen option 4!: Display a matix!" << endl;
                cout << "Please enter the option 1, 2 or 3 to display the respective matrices!" << endl;
                cin >> whichMatrixToDisplay;
                if(whichMatrixToDisplay == '1')
                    m1.displayMatrix();
                else if(whichMatrixToDisplay == '2')
                    m2.displayMatrix();
                else if(whichMatrixToDisplay == '3')
                    m3.displayMatrix();
                else
                cout << endl;
                break;
 
            case '5':
                cout << "You have chosen the option to Quit. Goodbye!" << endl;
                break;
 
            default:
                cout << " Sorry the option chosen is invalid. Please enter a valid option!" << endl << endl;
                break;
        }
    }
 
    return 0;
}