def dw_WriteNrExChanges(fname, nr):
    """ 
    Writes the number of exchnages to file (number of rows in the pointer file)
    
    B4\\_nrofexch.inc
    """
    exfile = open(fname, 'w')
    print(';Written by dw_WriteNrExChnages', file=exfile)
    print(str(nr) + ' 0 0 ; x, y, z direction', file=exfile)
    exfile.close()
