使用通用案例进行开关改进

时间:2019-03-19 01:22:56

标签: c performance for-loop switch-statement

是否可以更改此“开关”?首先,我虽然可以使用“ for”代替,但我认为不再需要了。目的是使此代码更有效。有人知道如何进行改进以使代码更高效吗?我仍在学习编程,但经验不足。我已经做了一些事情,但是我不知道它是否缺少什么,所以我将新代码放在旧代码的下面。我认为可能有必要使用if代替我创建的for或其他函数,因为我无法更改'PageNumber'的值,我只需要使用它即可。也许我不需要使用“案例”中已经存在的任何东西。有人可以澄清一下吗?

switch (PageNumber) {

            case 0x01:
                m = 0;
                for (n = 0; n < 8; n++) {
                    if (n < NumberOfSensor) {
                        if (n < 4) {
                            Write_string("L       ", n, 0);
                            Write_int((n + 1), n, 1);
                            write_CustonCharacter(4, n, 3); //Write the indicator "->"


Write_int(Sensor_Count[n], n, 5);
                            } else if (n > 3) {
                                Write_string("L       ", (n - 4), 10);
                                Write_int((n + 1), (n - 4), 11);
                                write_CustonCharacter(4, (n - 4), 13); //Write the indicator "->"
                                Write_int(Sensor_Count[n], (n - 4), 15);
                            }

                        }
                    }
                    break;


                    /*
                     * PAGE 2
                     */
                case 0x02:

                    m = 0;
                    for (n = 8; n < 16; n++) {
                        if (n < NumberOfSensor) {
                            if (n < 12) {
                                Write_string("L       ", (n - 8), 0);
                                Write_int((n + 1), (n - 8), 1);
                                write_CustonCharacter(4, (n - 8), 3); //Write the indicator "->"
                                Write_int(Sensor_Count[n], (n - 8), 5);
                            } else if (n > 11) {
                                Write_string("L       ", (n - 12), 10);
                                Write_int((n + 1), (n - 12), 11);
                                write_CustonCharacter(4, (n - 12), 13); //Write the indicator "->"
                                Write_int(Sensor_Count[n], (n - 12), 15);
                            }

                        }
                    }
                    break;


                    //...(This part is just repetition)

                    /*
                     * PAGE 8
                     */
                case 0x08:
                    m = 0;
                    for (n = 56; n < 65; n++) {
                        if (n < NumberOfSensor) {
                            if (n < 60) {
                                Write_string("L       ", (n - 56), 0);
                                Write_int((n + 1), (n - 56), 1);
                                write_CustonCharacter(4, (n - 56), 3); //Write the indicator "->"
                                Write_int(Sensor_Count[n], (n - 56), 5);
                            } else if (n > 59) {
                                Write_string("L       ", (n - 60), 10);
                                Write_int((n + 1), (n - 60), 11);
                                write_CustonCharacter(4, (n - 60), 13); //Write the indicator "->"
                                Write_int(Sensor_Count[n], (n - 60), 15);
                            }

                        }
                    }
                    break;
                default:
                    break;
                }
//==========================================================================
                for (PageNumber = 1; PageNumber < 9; PageNumber++) { //actually I think this for is not necessary because it receives PageNumber and then it does what it needs to do.
                    m = 0; //but does it need something else?
                    for (n = (PageNumber * 8 - 8); n < (PageNumber * 8); n++) {
                        if (n < NumberOfSensor) {
                            if (n < (PageNumber * 8 - 4)) {
                                Write_string("L       ", n - (PageNumber * 8 - 8), 0);
                                Write_int((n + 1), n - (PageNumber * 8 - 8), 1);
                                write_CustonCharacter(4, n - (PageNumber * 8 - 8), 3); //Write the indicator "->"
                                Write_int(Sensor_Count[n], n - (PageNumber * 8 - 8), 5);
                            } else if (n > (PageNumber * 8 - 5)) {
                                Write_string("L       ", n - (PageNumber * 8 - 4), 10);
                                Write_int((n + 1), n - (PageNumber * 8 - 4), 11);
                                write_CustonCharacter(4, n - (PageNumber * 8 - 4), 13); //Write the indicator "->"
                                Write_int(Sensor_Count[n], n - (PageNumber * 8 - 4), 15);
                            }

                        }
                    }

                }

1 个答案:

答案 0 :(得分:4)

首先,我想说这段代码的效率不高,主要是因为它在重复自身,而不是因为内存使用情况。

如何在这方面进行改进-您只能有一个for循环而根本没有开关箱。

如何?尝试将每种情况下的for循环表示为case值的函数,然后根据其他for循环体将其概括。例如:

请注意,对于每种情况:

  • for循环的初始值始终为Axiom Axiom3: forall A B: Prop, (~A -> ~B)-> ((~A -> B) -> A). Lemma classical : forall A : Prop, A \/ ~ A. Proof. intros A. apply (Axiom3 (A \/ ~A) (A \/ ~A)). - trivial. - intros H. exfalso. assert (H' : ~ ~ A). { intros HA. apply H. right. trivial. } apply H'. intros HA. apply H. left. trivial. Qed.
  • for循环条件始终为(PageNumber-1)*8
  • n < PageNumber*8子句中的第一行始终为if-then

以此类推。 继续归纳每个随Write_string("L ", (n-((PageNumber-1)*8), 0));而变化的数字,然后最终将只有一个for循环而根本没有切换情况。