#define _N 4
int A[ _N * _N ][ _N ];
int i;
int j;
int b;
for ( i = 0; i < _N * _N; i++ ) for ( b = 0x00000001, j = 0; j < _N; b <<= 1,j++ ) A[ i ][ _N - j - 1 ] = ( i & b ) ? 1 : 0;