Linear Algebra and the C Language/a05e

Install and compile this file in your working directory.

/* ------------------------------------ */
/*  Save as :   cof_r.c                 */
/* ------------------------------------ */
#include "v_a.h"
/* ------------------------------------ */
void fun(int n)
{
double **A = r_mR(i_mR(n,n),99.);

int r = rp_I(n);
int c = rp_I(n);

  clrscrn();
  printf(" A :");
  p_mR(A,S5,P0,C6);

  printf("    minor(R%d,C%d) = %+.3f\n"
         " cofactor(R%d,C%d) = %+.3f\n\n\n",
               r,c,    minor_R(A, r,c),
               r,c, cofactor_R(A, r,c));
               
  printf(" cofactor(R%d,C%d) = minor(R%d,C%d)*(-1**(R%d+C%d))\n"
         "                   = minor(R%d,C%d)*(%0.0f)\n",
                    r,c, r,c, r,c, r,c, pow(-1,(r+c)));
  
  f_mR(A);
}
/* ------------------------------------ */
int main(void)
{
time_t t;

  srand(time(&t));
do
{
  fun(rp_I(RC5)+C1);

 } while(stop_w());

  return 0;
}
/* ------------------------------------ */
/* ------------------------------------ */

Screen output example:

 A :
  +22    -6 
  +79   +92 

    minor(R1,C1) = +92.000
 cofactor(R1,C1) = +92.000


 cofactor(R1,C1) = minor(R1,C1)*(-1**(R1+C1))
                 = minor(R1,C1)*(1)

 Press   return to continue
 Press X return to stop