void PrintWordsInRow(const apmatrix<char> & crossWord, int r)
// precondition: crossWord contains only uppercase letters or spaces    
//               0 <= r < crossWord.numrows()
// postcondition: prints the words in row with index r of crossWord,
//                one word per line
{
    int k;
    int cols = crossWord.numcols();

    k = 1;       // avoid boundary
    while(k < cols-1)
    {
	// check if at least two non-space characters in a row
	if (crossWord[r][k] != ' ' && crossWord[r][k+1] != ' ')
	{
	    // loop is safe because boundary is spaces
	    while (crossWord[r][k] != ' ')
	    {
		cout << crossWord[r][k];
		k++;
	    }
	    cout << endl;
	}
	k++;    // this is safe (loop exits on space)
    }
}