Question

所以我需要帮助将if else语句更改为switch case语句，因为我是arduino编码的新手，似乎无法让它工作。该程序应该闪烁LED，发出扬声器，点亮灯泡，旋转风扇，并在if else语句中的条件满足时，将选定的信息显示在16x2 lCD上。

    #include <LiquidCrystal.h>

    //Pins of LCD     RS  E  D4 D5  D6 D7
    LiquidCrystal lcd(7, 8, 9, 10, 11, 12); // Pins of Arduino 
    int tempPin = A0; //LM35 Pin
    int ldrPin = A1;  //LDR Pin
    int led = 6;    //LED Pin
    int tempMax = 100;
    int buzzer = 13;
    float temp;
    float tempC; 
    int lightReading; 
    int numTones = 2;
    int tones[] = {440, 349};
    int TIP120pin = 5;
    int bulb = A2;

    void setup()
    {
      lcd.begin(16, 2);

      Serial.begin(9600);

      pinMode(led, OUTPUT);

      pinMode(tempPin, INPUT);

      pinMode(ldrPin, INPUT);

      pinMode(buzzer,OUTPUT); 

      pinMode(TIP120pin, OUTPUT);

      pinMode(bulb, OUTPUT);

      lcd.clear();
      beep(100);
    }
    void loop()
    {
      tempC = (5.0 * analogRead(tempPin) * 100.0) / 1024;
      temp = tempC;
      lightReading = analogRead(ldrPin);

        lcd.print("TEMP:");
        lcd.setCursor(5, 0);
        lcd.print(temp);      // display the temperature
        lcd.print("C");

        // Display Light on second row
        lcd.setCursor(0, 1);
        lcd.print("Light           ");
        lcd.setCursor(6, 1);
        lcd.print(lightReading);
        delay(500);
        analogWrite(TIP120pin, 0);
        analogWrite(bulb, 0);

      if (temp >=35)  // if temp is higher than max temp
      {
       lcd.clear();
       analogWrite(TIP120pin, 255);
       lcd.setCursor(3, 0);
        lcd.print("Room Hot!!");
        digitalWrite(led, HIGH);
        delay(200);
        beep(50);
        digitalWrite(led, LOW);
        delay(200);
      }

      else if (temp >=30 && temp<35)
      {
        lcd.clear();
        analogWrite(TIP120pin, 255);
        digitalWrite(led, HIGH);
        delay(200);
        beep(50);
        digitalWrite(led, LOW);
        delay(200); 
        lcd.setCursor(3, 0);
        lcd.print("Room Warm!");
        delay(200);

      }
     else if (lightReading >100 && lightReading <= 200)
      {
        lcd.clear();
        analogWrite(bulb, 150);
        digitalWrite(led, HIGH);
        delay(200);
        beep(50);
        digitalWrite(led, LOW);
        delay(200); 
        // Display Light on second row
        lcd.setCursor(3, 0);
        lcd.print("Room Dim");
        delay(200);
        analogWrite(TIP120pin, 0);
      }
      else if (lightReading <=100)
      {
        lcd.clear();
        analogWrite(bulb, 255);
        digitalWrite(led, HIGH);
        delay(200);
        beep(50);
        digitalWrite(led, LOW);
        delay(200);
        lcd.setCursor(3, 0);  
        lcd.print("Room Dark");
        delay(200);
        analogWrite(TIP120pin, 0);
      }    

      else if(temp>=35 && lightReading>100 && lightReading<=200)
      {
        lcd.clear();
        analogWrite(bulb, 150);
        analogWrite(TIP120pin, 255);
        digitalWrite(led, HIGH);
        delay(200);
        beep(50);
        digitalWrite(led, LOW);
        delay(200);
        lcd.setCursor(3, 0);  
        lcd.print("Room Hot!");
        lcd.setCursor(3, 1);
        lcd.print("Room Dim!");
        delay(200);
      }

      else if(temp>=35 && lightReading<=100)
      {
        lcd.clear();
        analogWrite(bulb, 255);
        analogWrite(TIP120pin, 255);
        digitalWrite(led, HIGH);
        delay(200);
        beep(50);
        digitalWrite(led, LOW);
        delay(200);
        lcd.setCursor(3, 0);  
        lcd.print("Room Hot!");
        lcd.setCursor(3, 1);
        lcd.print("Room Dark!");
        delay(200);
      }

      else if(temp>=30 && temp<35 && lightReading>=100 && lightReading <=200)
      {
        lcd.clear();
        analogWrite(bulb, 150);
        analogWrite(TIP120pin, 150);
        digitalWrite(led, HIGH);
        delay(200);
        beep(50);
        digitalWrite(led, LOW);
        delay(200);
        lcd.setCursor(3, 0);  
        lcd.print("Room Warm!");
        lcd.setCursor(3, 1);
        lcd.print("Room Dim!");
        delay(200);
      }

      else if (temp>=30 && temp<35 && lightReading<100)
      {
        lcd.clear();
        analogWrite(bulb, 255);
        analogWrite(TIP120pin, 255);
        digitalWrite(led, HIGH);
        delay(200);
        beep(50);
        digitalWrite(led, LOW);
        delay(200);
        lcd.setCursor(3, 0);  
        lcd.print("Room Hot!!");
        lcd.setCursor(3, 1);
        lcd.print("Room Dark!");
        delay(200);
      }

      else  
      {
        digitalWrite(led, LOW);
        digitalWrite(buzzer, LOW);
        analogWrite(bulb, LOW);
        lcd.print("TEMP:");
        lcd.setCursor(5, 0);
        lcd.print(temp);      
        lcd.print("C");

        // Display Light on second row
        lcd.setCursor(0, 1);
        lcd.print("Light           ");
        lcd.setCursor(6, 1);
        lcd.print(lightReading);
      }
      delay(500);
      lcd.clear();
      Serial.print("Light,   "); Serial.print(lightReading); Serial.print('\n');
    }
    void beep(unsigned char delayms){
      for(int x=0; x<numTones; x++)
        {
        tone(buzzer, tones[x]);
        delay(delayms);
        }
      noTone(buzzer);  
      }

Answer 1

在Java中，switch语句采用以下形式：

switch (expression)
{ 
  case constant:
        statements;
        break;
  [ case constant-2:
        statements;
        break;  ] ...
  [ default:
        statements;
        break;  ] ...
}

switch语句适用于byte，short，char和int原语数据类型。它还适用于枚举类型，String类和一些包含某些基本类型的特殊类：Character，Byte，Short和Integer。

你的嵌套ifs及其布尔表达式不适合切换。

Answer 2

如果你想将if语句转换为Switch，即我假设你想提高代码的可读性，可以在循环中使用if语句并将switch放入函数中..检查下面的代码

<div id=rdTest>
<div class="inputField">
    <label>Focal Image:</label>
    <input name="FocalImage" type="text" id="field_2" class="textbox" value="">
</div>
<div class="radioGroup">
    <label>Test Page:</label>
    <input type="radio" name="toggle" value="Yes" id="tglyes">Yes
    <input type="radio" name="toggle" value='No' id="tglno">No
</div>
<div id="thgtLdr"></div>
</div>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js"></script>
<script> // place code here </script>

并将你的不同条件放在doSomething（）函数的switch语句中，如下所示

void loop()
{
  tempC = (5.0 * analogRead(tempPin) * 100.0) / 1024;
  temp = tempC;
  lightReading = analogRead(ldrPin);

    lcd.print("TEMP:");
    lcd.setCursor(5, 0);
    lcd.print(temp);      // display the temperature
    lcd.print("C");

    // Display Light on second row
    lcd.setCursor(0, 1);
    lcd.print("Light           ");
    lcd.setCursor(6, 1);
    lcd.print(lightReading);
    delay(500);
    analogWrite(TIP120pin, 0);
    analogWrite(bulb, 0);

  if (temp >=35)  // if temp is higher than max temp
  {
   doSomething('a');
  }

  else if (temp >=30 && temp<35)
  {
  doSomething('b');
  }
 else if (lightReading >100 && lightReading <= 200)
  {
  doSomething('c');
  }
  else if (lightReading <=100)
  {
    doSomething('d');
  }    

  else if(temp>=35 && lightReading>100 && lightReading<=200)
  {
    doSomething('e');
  }

  else if(temp>=35 && lightReading<=100)
  {
    doSomething('f');
  }

  else if(temp>=30 && temp<35 && lightReading>=100 && lightReading <=200)
  {
    doSomething('g');
  }

  else if (temp>=30 && temp<35 && lightReading<100)
  {
    doSomething('h');
  }

  else  
  {
      doSomething('i');
  }

需要帮助将else语句更改为switch case

2 个答案: