Linear Algebra and the C Language/a0g0

/* ------------------------------------ */
/*  Save as :   c00b.c                  */
/* ------------------------------------ */
#include      "v_a.h"
/* ------------------------------------ */
int main(void)
{
double  a[R3*C3]={ 1,1,1,
                   2,9,9,
                   3,9,9 };	

double id[R3*C3]={ 1,0,0,
                  -2,1,0,
                  -3,0,1 };                
              
double **A  = ca_A_mR(a, i_mR(R3,C3));
double **ID = ca_A_mR(id,i_mR(R3,C3));

double **IDA = mul_mR(ID,A,i_mR(R3,C3));

  clrscrn();
  printf(" Zero under the pivot \n\n");
  
  printf(" ID:");
  p_mR(ID, S3,P0,C6);
  
  printf(" A:");
  p_mR(A, S3,P0,C6);
  
  printf(" ID A:");
  p_mR(IDA, S3,P1,C6);
  stop();
     
  f_mR(A);
  f_mR(ID);
  f_mR(IDA);
  return 0;
}
/* ------------------------------------ */
/* ------------------------------------ */

                                                                                       
 Zero under the pivot 

 ID:
 +1  +0  +0 
 -2  +1  +0 
 -3  +0  +1 

 A:
 +1  +1  +1 
 +2  +9  +9 
 +3  +9  +9 

 ID A:
+1.0 +1.0 +1.0 
+0.0 +7.0 +7.0 
+0.0 +6.0 +6.0 

 Press return to continue.