### Question:
CNExpression { public int calculate(){ if(op<0|num1<0|num2<0) return -1; switch(op){ case 0: ans=num1+num2; break; case 1: ans=num1-num2; break; case 2: ans=num1*num2; break; case 3: ans=num1/num2; break; case 4: ans=num2/num1; break; default: return -1; } return 0; } CNExpression(); int getAns(); String getAnswerInChn(); boolean setExpr(String str); int chn2Num(String str); int chn2Num(String str,Loc loc); int calculate(); String num2Chn(int num);  }### Answer:
@Test public void testCalculate() { }