/* I am offering the following as a time-saver in doing the problem of
matrix reduction. The following is what one student wrote two years ago.
Except I deleted the calculations, leaving you with the input-output
routines. I am doing this because those routines present difficulties
that have very little to do with the mathematics of this course. You can
use this more or less as is, or modify it slightly. The way it's written
you enter a square matrix. Of course any matrix can be handled this way,
since you can make a matrix square by adding zeros. Nevertheless, it might
be slightly nicer to ask for both the number of rows and the number of
columns, and then display the matrix accordingly. The routine ouptut()
shows what I want: I want a calculation of the determinant; if this determinant
is non-zero, then the inverse is calculated; if zero, then a row- (or column-)
reduction is given. All these calculations can be made in parallel if
you follow the outline on page 35. See also Exercise 12 on page 52. 

You can compile and run this program as is; it of course won't give the
right answer, but it will give you a feeling for how the program should
feel when it runs. You won't see the alternative of det=0 when you do
it this way.

This is only a suggestion. There are other good ways to do it.

Please include in your program a statement that you have not previously
done this exercise or something similar in another course.                 */

#include <stdio.h>

#define	MAX	50
float mat[2*MAX][MAX];
int n;
float det=1.;


/*******************************************************************/
main ()
{
input();
calc();
output();
}

/*******************************************************************/
calc()
{
}

/******************************************************************/
input()
{
int i,j,k;

printf("Input the size of the matrix: ");
scanf("%d",&n);
printf("\n");

printf("Input the matrix (by rows):\n");
for (i=0; i<n; i++)
{
  for (j=0; j<n; j++)
  {
    scanf("%f",&mat[j][i]);
  }
}
printf("\n");
}

/******************************************************************/
output()
{
int i,j,k;

printf("Determinant is: %f \n",det);
printf("\n");
if (det == 0)
{
  printf("Singular matrix - Inverse does not exist - Reduced form:\n");
  for (i=0; i<n; i++) 
  {
    for (j=0; j<n; j++)
    {
      printf("	%6.2f",mat[j][i]);
    }
    printf("\n");
  }
}
else
{
  printf("Inverse is: \n");
  for (i=0; i<n; i++) 
  {
    for (j=0; j<n; j++)
    {
      printf("	%6.2f",mat[j][i]);
    }
    printf("\n");
  }
}
}