If 语句在 ESP32 上没有按预期工作
If statements not working as expected on ESP32
我的实验遇到了一些令人费解的情况。我只是使用电容传感器测量土壤湿度并通过 nodemcu 的模拟引脚读取。之后,我将土壤状况分类为潮湿、中等或干燥。我想为此使用简单的 if-else 语句。但是,出于某种原因,它们没有按预期工作。只有先if被执行,不该满足的条件才满足...
const int SOIL_MOISTURE_DATA_NOT_FOUND = 0;
const int SOIL_TOO_WET = 1;
const int SOIL_MID_LEVEL_MOISTURE = 2;
const int SOIL_TOO_DRY = 3;
当我使用 else if 语句时,它只执行第一条语句和 returns..
int soilStatus = SOIL_MOISTURE_DATA_NOT_FOUND;
int rawHumiditySensorValue = analogRead(A0);
Serial.print("Moisture value : ");
Serial.println(rawHumiditySensorValue);
if( 500 < rawHumiditySensorValue <= 750 )
{
Serial.println("SOIL_TOO_WET");
soilStatus = SOIL_TOO_WET;
}
else if( 750 < rawHumiditySensorValue <= 820 )
{
soilStatus = SOIL_MID_LEVEL_MOISTURE;
Serial.println("SOIL_MID_LEVEL_MOISTURE");
}
else if( 820 < rawHumiditySensorValue <= 920 )
{
soilStatus = SOIL_TOO_DRY;
}
// Invalid reading / no reading cases:
else if( rawHumiditySensorValue < 500 || rawHumiditySensorValue > 1000 )
{
soilStatus = SOIL_MOISTURE_DATA_NOT_FOUND;
}
Serial.print("Soil Status :");
Serial.println(soilStatus);
串行监视器的输出:
我删除了 if else,无论变量值如何,所有 if 语句都会被执行
int soilStatus = SOIL_MOISTURE_DATA_NOT_FOUND;
int rawHumiditySensorValue = analogRead(A0); //readAnalogDataFromHydroSensor(pinID);
Serial.print("Moisture value : ");
Serial.println(rawHumiditySensorValue);
if( 500 < rawHumiditySensorValue <= 750 )
{
Serial.println("SOIL_TOO_WET");
soilStatus = SOIL_TOO_WET;
}
if( 750 < rawHumiditySensorValue <= 820 )
{
soilStatus = SOIL_MID_LEVEL_MOISTURE;
Serial.println("SOIL_MID_LEVEL_MOISTURE");
}
if( 820 < rawHumiditySensorValue <= 920 )
{
soilStatus = SOIL_TOO_DRY;
}
// Invalid reading / no reading cases:
if( rawHumiditySensorValue < 500 || rawHumiditySensorValue > 1000 )
{
soilStatus = SOIL_MOISTURE_DATA_NOT_FOUND;
}
Serial.print("Soil Status :");
Serial.println(soilStatus);
我在串行监视器上得到以下输出:
我在这里错过了什么?我检查了所有本地变量的数据类型,都设置为 int.
关系运算符是具有从左到右结合性的二元运算符。结果为 0 或 1。
表达式500 < rawHumiditySensorValue <= 750
等价于(500 < rawHumiditySensorValue) <= 750
。由于 (500 < rawHumiditySensorValue)
的结果将为 0 或 1,并且这两个值都小于或等于 750,因此整个表达式的结果为 1。
您可能想要的是 500 < rawHumiditySensorValue && rawHumiditySensorValue <= 750
。
您可以使用 else if
:
简化代码中关系运算符的使用
// Invalid reading / no reading cases:
if( rawHumiditySensorValue < 500 || rawHumiditySensorValue > 1000 )
{
soilStatus = SOIL_MOISTURE_DATA_NOT_FOUND;
}
else if( rawHumiditySensorValue <= 750 )
{
soilStatus = SOIL_TOO_WET;
}
else if( rawHumiditySensorValue <= 820 )
{
soilStatus = SOIL_MID_LEVEL_MOISTURE;
}
else if( rawHumiditySensorValue <= 920 )
{
soilStatus = SOIL_TOO_DRY;
}
else
{
soilStatus = SOIL_FAR_TOO_DRY; /* Original code did not handle this case! */
}
我的实验遇到了一些令人费解的情况。我只是使用电容传感器测量土壤湿度并通过 nodemcu 的模拟引脚读取。之后,我将土壤状况分类为潮湿、中等或干燥。我想为此使用简单的 if-else 语句。但是,出于某种原因,它们没有按预期工作。只有先if被执行,不该满足的条件才满足...
const int SOIL_MOISTURE_DATA_NOT_FOUND = 0;
const int SOIL_TOO_WET = 1;
const int SOIL_MID_LEVEL_MOISTURE = 2;
const int SOIL_TOO_DRY = 3;
当我使用 else if 语句时,它只执行第一条语句和 returns..
int soilStatus = SOIL_MOISTURE_DATA_NOT_FOUND;
int rawHumiditySensorValue = analogRead(A0);
Serial.print("Moisture value : ");
Serial.println(rawHumiditySensorValue);
if( 500 < rawHumiditySensorValue <= 750 )
{
Serial.println("SOIL_TOO_WET");
soilStatus = SOIL_TOO_WET;
}
else if( 750 < rawHumiditySensorValue <= 820 )
{
soilStatus = SOIL_MID_LEVEL_MOISTURE;
Serial.println("SOIL_MID_LEVEL_MOISTURE");
}
else if( 820 < rawHumiditySensorValue <= 920 )
{
soilStatus = SOIL_TOO_DRY;
}
// Invalid reading / no reading cases:
else if( rawHumiditySensorValue < 500 || rawHumiditySensorValue > 1000 )
{
soilStatus = SOIL_MOISTURE_DATA_NOT_FOUND;
}
Serial.print("Soil Status :");
Serial.println(soilStatus);
串行监视器的输出:
我删除了 if else,无论变量值如何,所有 if 语句都会被执行
int soilStatus = SOIL_MOISTURE_DATA_NOT_FOUND;
int rawHumiditySensorValue = analogRead(A0); //readAnalogDataFromHydroSensor(pinID);
Serial.print("Moisture value : ");
Serial.println(rawHumiditySensorValue);
if( 500 < rawHumiditySensorValue <= 750 )
{
Serial.println("SOIL_TOO_WET");
soilStatus = SOIL_TOO_WET;
}
if( 750 < rawHumiditySensorValue <= 820 )
{
soilStatus = SOIL_MID_LEVEL_MOISTURE;
Serial.println("SOIL_MID_LEVEL_MOISTURE");
}
if( 820 < rawHumiditySensorValue <= 920 )
{
soilStatus = SOIL_TOO_DRY;
}
// Invalid reading / no reading cases:
if( rawHumiditySensorValue < 500 || rawHumiditySensorValue > 1000 )
{
soilStatus = SOIL_MOISTURE_DATA_NOT_FOUND;
}
Serial.print("Soil Status :");
Serial.println(soilStatus);
我在串行监视器上得到以下输出:
我在这里错过了什么?我检查了所有本地变量的数据类型,都设置为 int.
关系运算符是具有从左到右结合性的二元运算符。结果为 0 或 1。
表达式500 < rawHumiditySensorValue <= 750
等价于(500 < rawHumiditySensorValue) <= 750
。由于 (500 < rawHumiditySensorValue)
的结果将为 0 或 1,并且这两个值都小于或等于 750,因此整个表达式的结果为 1。
您可能想要的是 500 < rawHumiditySensorValue && rawHumiditySensorValue <= 750
。
您可以使用 else if
:
// Invalid reading / no reading cases:
if( rawHumiditySensorValue < 500 || rawHumiditySensorValue > 1000 )
{
soilStatus = SOIL_MOISTURE_DATA_NOT_FOUND;
}
else if( rawHumiditySensorValue <= 750 )
{
soilStatus = SOIL_TOO_WET;
}
else if( rawHumiditySensorValue <= 820 )
{
soilStatus = SOIL_MID_LEVEL_MOISTURE;
}
else if( rawHumiditySensorValue <= 920 )
{
soilStatus = SOIL_TOO_DRY;
}
else
{
soilStatus = SOIL_FAR_TOO_DRY; /* Original code did not handle this case! */
}