/* 
 
 Written by:
 -- 
 John L. Weatherwax                2006-05-30
 
 email: wax@alum.mit.edu
 
 Please send comments and especially bug reports to the
 above email address.
 
-----
*/ 

#include "sub2ind.h"


/* A block row version -- compatable with C's conventions if 
   M=4 & N=3 then given a subscript (the pair of numbers in the below)
   this routine returns the first number below

   0=(0,0)    1=(0,1)     2=(0,2)
   3=(1,0)    4=(1,1)     5=(1,2)
   6=(2,0)    7=(2,1)     8=(2,2)
   9=(3,0)    10=(3,1)    11=(3,2)

*/ 
int sub2ind(int M, int N, int i, int j){

  return i*N+j; 
}

void test_sub2ind(void){

  int M,N,ind,i,j;

  M=4; N=3; 
  for( i=0; i < M; i++ ){
    for( j=0; j < N; j++ ){
      ind = sub2ind(M,N,i,j);
      printf("(i,j)=(%d,%d); ind=%d\n",i,j,ind);
    }
  }
}