public Eq dpart() { if (this.operat == "d") { return(this); } else { if (operand2 != null) { if (operand2.dpart() == null) { return(operand1.dpart()); } return(operand2.dpart()); } else if (operand1 != null) { return(operand1.dpart()); } else { return(null); } } }