c - 使用通用案例进行开关改进

Question

是否可以更改此“开关”？首先，我虽然可以使用“for”来代替，但我认为不再需要了。目的是使此代码更高效。有谁知道如何进行此改进以使代码更高效？我还在学习编程，我还没有那么有经验。我已经做了一些事情，但我不知道它是否缺少我将新代码放在旧代码下的东西。我认为可能有必要使用 if 而不是我创建的 for 或其他函数，因为我无法更改 'PageNumber' 的值，我只需要使用它。也许我不需要使用任何已经在“案例”中的东西。有人可以帮我解释一下吗？

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);
                            }

                        }
                    }

                }

Answer 1

首先，我要说这段代码效率不高主要是因为它在重复自己，而不是因为内存使用。

您如何在这方面改进它 - 您可以只有一个 for 循环而根本没有 switch-case。

如何？尝试将每个案例中的 for 循环表示为案例值的函数，然后根据其他 for 循环主体对其进行概括。例如:

请注意，对于每种情况:

• for 循环的初始值总是(PageNumber-1)*8
• for 循环条件总是 n < PageNumber*8
• 第一行里面if-then子句总是 Write_string("L ", (n-((PageNumber-1)*8), 0));

等等。继续概括每个随 PageNumber 变化的数字。然后你最终将只有一个 for 循环，根本没有 switch-case。