需要帮助将 if else 语句更改为 switch case

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。当满足 if else 语句中的条件时，该程序应该使 LED 灯闪烁、扬声器发出声音、灯泡点亮、风扇旋转并在 16x2 液晶显示器上显示所选消息。

    #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 原始数据类型。它还适用于枚举类型、字符串 class 和一些包装某些基本类型的特殊 classes：Character、Byte、Short 和 Integer。

您的带有布尔表达式的嵌套 if 不适合 switch。

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，你可以在循环中使用 if 语句并将 switch 放在函数中..检查下面的代码

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');
  }

然后将您的不同条件放入 doSomething() 函数的 switch 语句中，如下所示

void doSomething(condition){
switch(condition){    
case 'a' :  // 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);
break;

case 'b' :

  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);
break;

case 'c' :
  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);
break;

case 'd':

  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);
break;    

case 'e':

  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);
break;

case 'f':
  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);
break;

case 'g':
  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);
break;

case 'h':
  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);
break;


default:
  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);
break; 
}
}

需要帮助将 if else 语句更改为 switch case

Need help changing if else statements into switch case

arduino

switch-statement

arduino-uno