1. ## Matrix

What is the header file for matrixes?

How would I use a matrix to add information into a file, and then retrieve the information from the file?

2. In my opinion a matrix is just a 2x2 array. As far as I know there is no special header file for it. Why would you need such header file?

3. I thought it was matrix.h, but it doesn't seem to work. How would I declare and initiate a matrix?

4. What is the matrix?

5. Matrix = 2D array.

int matrix[2][2]; // initializes a 2X2 "matrix" (array) of int's
double matrix[2][60]; //initialized a 2X60 of doubles

No header file needed. It's built into C++.

If you are talking about apmatrix used in apcs, it's apmatrix.h, but you have to download it somewhere. But don't use that cuz it's slow and crappy.

6. ## this is the matrix

here take this code if u want to understand matrix

//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop
#pragma argsused
#include <iostream>
#include <conio>

using namespace std;

//---------------------------------------------------------------------------

int main()
{
int i, j;
int x[3][3], y[3][3], z[3][3];

//**************** first Matrix Starts Here ******************************//
for( i = 0; i < 3; i++)
{
for( j =0; j < 3; j++)
{
cout << "Enter a Integer for First Matrix:-" << "\n";
cin >> x[i][j];
}
}
cout << "\nThe First Matrix" << "\n";
for( i = 0; i < 3; i++)
{
for( j =0; j < 3; j++)
{
cout << x[i][j] ;
}
cout << "\n" ;
}

//*************** Second Matrix Starts here ***************************//
for( i = 0; i < 3; i++)
{
for( j =0; j < 3; j++)
{
cout << "Enter a Integer for Second Matrix:-" << "\n";
cin >> y[i][j];
}
}
cout << "The Second Matrix" << "\n";
for( i = 0; i < 3; i++)
{
for( j =0; j < 3; j++)
{
cout << y[i][j] ;
}
cout << "\n" ;
}

//*************** Sum Of Matrix *****************************************//

cout << "\nSum Of Matrix:-" << "\n";

for( i = 0; i < 3; i++)
{
for( j = 0; j < 3; j++)
{
z[i][j] = x[i][j] + y[i][j];
cout << z[i][j];
}
cout << "\n";
}

//*************** Multiplication Of Matrix ******************************//

cout << "\nMultiplication Of Matrix :-" << "\n";

for( i = 0; i < 3; i++)
{
for( j = 0; j < 3; j++)
{
z[i][j] = x[i][0] * y[0][j] + x[i][1] * y[1][j] + x[i][2] * y[2][j];
cout << z[i][j];
}
cout << "\n";
}

getch();
return 0;
}
//---------------------------------------------------------------------------