c++ - C++ 嵌套的 If 语句，它没有按预期工作
问题描述
StackOverflow 开发人员，
我正在做一些 Arduino 编码来测量细粉尘监测设备，
但是，我有一个关于 If 语句的问题。
在下面的代码中，我在 while 循环中添加了嵌套 if 语句，出于某种原因，
else if (9999 >= int(pm25s.getMedian()) && int(pm25s.getMedian()) >= 52) {
pm25i = 7;
}
else if (9999 >= int(pm10s.getMedian()) && int(pm10s.getMedian()) >= 102) {
pm10i = 7;
}
else if (pm10i == 7) {
status = "Hazardous (7) : Health warnings of emergency conditions. People at risk should be avoided to go outside and should limit the outdoor activities to minimum. Outdoor activities are strongly discouraged.";
}
}
这些行没有按预期工作，因为当 pm10 或 pm25 值达到超过 100 ug / m^3 时，它不再与 ThingSpeak 服务器同步，但我不知道为什么它不上传任何数据. 有趣的是，我的源代码部分的其余部分可以正常工作。
但是，当我删除那些嵌套的 if 语句时，它工作正常。（即使 pm10 或 pm25 值达到 100 ug/m^3 以上，它也能成功上传。
有人可以解释我的代码有什么问题吗？请问我应该如何解决这个问题？
谢谢。
void loop() {
if (ss.available() <= 0) {
Serial.println("SIGNAL STATUS : WEAK");
s_map_x = String(map_x, 6);
s_map_y = String(map_y, 6);
}
else {
while (ss.available() > 0) {
Serial.println("SIGNAL STATUS : GREAT");
if (gps.encode(ss.read())) {
Serial.println("GPS READ");
Serial.println(ss.read());
if (gps.location.isValid()) {
Serial.println("LOCATION : GREAT");
map_x = gps.location.lat();
map_y = gps.location.lng();
Serial.println(String(map_x, 6));
Serial.println(String(map_y, 6));
Serial.println(gps.satellites.value());
}
}
s_map_x = String(map_x, 6);
s_map_y = String(map_y, 6);
yield();
}
}
while (dust.available() > 0) {
do_dust(dust.read(), got_dust);
yield();
/* AQI (실시간 대기질 지수) 등급 분류를 위한 코드입니다.
실시간 대기질 기준 수치는 국제 표준인 WHO 대기질 수치 기준으로 분류합니다.
http://www.euro.who.int/__data/assets/pdf_file/0005/78638/E90038.pdf
https://airnow.gov/index.cfm?action=aqibasics.aqi */
// 초미세먼지 AQI (실시간 대기질 지수) 등급을 분류합니다.
// 0 이상 8 이하 : 1
// 9 이상 16 이하 : 2
// 17 이상 26 이하 : 3
// 27 이상 34 이하 : 4
// 35 이상 43 이하 : 5
// 44 이상 51 이하 : 6
// 52 이상 ∞ 이하 : 7
if (8 >= int(pm25s.getMedian()) && int(pm25s.getMedian()) >= 0) {
pm25i = 1;
}
else if (16 >= int(pm25s.getMedian()) && int(pm25s.getMedian()) >= 9) {
pm25i = 2;
}
else if (26 >= int(pm25s.getMedian()) && int(pm25s.getMedian()) >= 17) {
pm25i = 3;
}
else if (34 >= int(pm25s.getMedian()) && int(pm25s.getMedian()) >= 27) {
pm25i = 4;
}
else if (43 >= int(pm25s.getMedian()) && int(pm25s.getMedian()) >= 35) {
pm25i = 5;
}
else if (51 >= int(pm25s.getMedian()) && int(pm25s.getMedian()) >= 44) {
pm25i = 6;
}
else if (9999 >= int(pm25s.getMedian()) && int(pm25s.getMedian()) >= 52) {
pm25i = 7;
}
// 미세먼지 AQI (실시간 대기질 지수) 등급을 분류합니다.
// 0 이상 8 이하 : 1
// 9 이상 16 이하 : 2
// 17 이상 51 이하 : 3
// 52 이상 68 이하 : 4
// 69 이상 84 이하 : 5
// 85 이상 101 이하 : 6
// 102 이상 ∞ 이하 : 7
if (8 >= int(pm10s.getMedian()) && int(pm10s.getMedian()) >= 0) {
pm10i = 1;
}
else if (16 >= int(pm10s.getMedian()) && int(pm10s.getMedian()) >= 9) {
pm10i = 2;
}
else if (51 >= int(pm10s.getMedian()) && int(pm10s.getMedian()) >= 17) {
pm10i = 3;
}
else if (68 >= int(pm10s.getMedian()) && int(pm10s.getMedian()) >= 52) {
pm10i = 4;
}
else if (84 >= int(pm10s.getMedian()) && int(pm10s.getMedian()) >= 69) {
pm10i = 5;
}
else if (101 >= int(pm10s.getMedian()) && int(pm10s.getMedian()) >= 85) {
pm10i = 6;
}
else if (9999 >= int(pm10s.getMedian()) && int(pm10s.getMedian()) >= 102) {
pm10i = 7;
}
/* ThingSpeak 채널 내 Status Update (상태 업데이트) 영역에 표시되는 문구이므로,
종합적인 정보 표현을 위해 초미세먼지와 미세먼지 등급을 비교 한 후
두 가지 중 높은 등급 기준으로 경고 혹은 권고메시지를 표시합니다. */
// 분류된 초미세먼지 등급이 미세먼지 등급보다 같거나 높은 경우, 초미세먼지 등급을 기준으로 내용을 표시하기 위하여 아래의 문자열을 status 변수에 저장합니다.
if (pm25i >= pm10i) {
if (pm25i == 1) {
status = "Excellent (1) : The air quality is excellent. The air pollution pose no threat. The conditions ideal for outdoor activities.";
}
else if (pm25i == 2) {
status = "Very Good (2) : Air quality is very good, and air pollution poses little or no risk. Conditions very good for outdoor activities.";
}
else if (pm25i == 3) {
status = "Moderate (3) : Air quality is acceptable. however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.";
}
else if (pm25i == 4) {
status = "Satisfactory (4) : Members of sensitive groups may experience health effects, Other people should limit spending time outdoors, especially when they experience symptoms such as cough or sore throat.";
}
else if (pm25i == 5) {
status = "Bad (5) : Everyone may begin to experience health effects, members of sensitive groups may experience more serious health effects. People at risk should avoid to go outside. Not recommended for outdoor activities.";
}
else if (pm25i == 6) {
status = "Severe (6) : Air quality is severe. Everyone may experience more serious health effects. People at risk should be avoided to go outside and should limit the outdoor activities to minimum. Outdoor activities are discouraged.";
}
else if (pm25i == 7) {
status = "Hazardous (7) : Health warnings of emergency conditions. People at risk should be avoided to go outside and should limit the outdoor activities to minimum. Outdoor activities are strongly discouraged.";
}
// 분류된 미세먼지 등급이 초미세먼지 등급보다 높은 경우, 미세먼지 등급을 기준으로 내용을 표시하기 위하여 아래의 문자열을 status 변수에 저장합니다.
} else if (pm25i < pm10i) {
if (pm10i == 1) {
status = "Excellent (1) : The air quality is excellent. The air pollution pose no threat. The conditions ideal for outdoor activities.";
}
else if (pm10i == 2) {
status = "Very Good (2) : Air quality is very good, and air pollution poses little or no risk. Conditions very good for outdoor activities";
}
else if (pm10i == 3) {
status = "Moderate (3) : Air quality is acceptable. however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.";
}
else if (pm10i == 4) {
status = "Satisfactory (4) : Members of sensitive groups may experience health effects, Other people should limit spending time outdoors, especially when they experience symptoms such as cough or sore throat.";
}
else if (pm10i == 5) {
status = "Bad (5) : Everyone may begin to experience health effects, members of sensitive groups may experience more serious health effects. People at risk should avoid to go outside. Not recommended for outdoor activities.";
}
else if (pm10i == 6) {
status = "Severe (6) : Air quality is severe. Everyone may experience more serious health effects. People at risk should be avoided to go outside and should limit the outdoor activities to minimum. Outdoor activities are discouraged.";
}
else if (pm10i == 7) {
status = "Hazardous (7) : Health warnings of emergency conditions. People at risk should be avoided to go outside and should limit the outdoor activities to minimum. Outdoor activities are strongly discouraged.";
}
}
}
//Serial.println(map_x);
//Serial.print("pm 25 : ");
//Serial.println(int(pm25s.getMedian()));
if (millis() > mark) {//one minute(60000) interval
mark = millis() + 60000;
got_interval = true;
}
if (got_interval) {
got_interval = false;
do_interval();
}
yield();
}
解决方案
由于浮点比较，您可能会遇到意外行为，或者可能是由于某些未处理的情况，或者可能是因为RunningMedian::getMedian()在任何/每个条件检查上都发生了变化。另一个可能的原因是可能RunningMedia::_cnt不超过 0。
另外，我建议将您的库更新到最新版本(v0.1.15)。
尝试将此代码放入while循环中：
float _pm25Median = pm25s.getMedian();
float _pm10Median = pm10s.getMedian();
if (isnan(_pm25Median) || isnan(_pm10Median))
continue; // or do something else to handle this exception properly
if (_pm25Median < 9)
pm25i = 1;
else if (_pm25Median < 17)
pm25i = 2;
else if (_pm25Median < 27)
pm25i = 3;
else if (_pm25Median < 35)
pm25i = 4;
else if (_pm25Median < 44)
pm25i = 5;
else if (_pm25Median < 52)
pm25i = 6;
else
pm25i = 7;
if (_pm10Median < 9)
pm10i = 1;
else if (_pm10Median < 17)
pm10i = 2;
else if (_pm10Median < 52)
pm10i = 3;
else if (_pm10Median < 69)
pm10i = 4;
else if (_pm10Median < 85)
pm10i = 5;
else if (_pm10Median < 102)
pm10i = 6;
else
pm10i = 7;
if (pm25i >= pm10i) {
switch (pm25i) {
case 1:
status = "Excellent (1) : The air quality is excellent. The air pollution pose no threat. The conditions ideal for outdoor activities.";
break;
case 2:
status = "Very Good (2) : Air quality is very good, and air pollution poses little or no risk. Conditions very good for outdoor activities.";
break;
case 3:
status = "Moderate (3) : Air quality is acceptable. however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.";
break;
case 4:
status = "Satisfactory (4) : Members of sensitive groups may experience health effects, Other people should limit spending time outdoors, especially when they experience symptoms such as cough or sore throat.";
break;
case 5:
status = "Bad (5) : Everyone may begin to experience health effects, members of sensitive groups may experience more serious health effects. People at risk should avoid to go outside. Not recommended for outdoor activities.";
break;
case 6:
status = "Severe (6) : Air quality is severe. Everyone may experience more serious health effects. People at risk should be avoided to go outside and should limit the outdoor activities to minimum. Outdoor activities are discouraged.";
break;
case 7:
status = "Hazardous (7) : Health warnings of emergency conditions. People at risk should be avoided to go outside and should limit the outdoor activities to minimum. Outdoor activities are strongly discouraged.";
default:
break;
}
} else {
switch (pm10i) {
case 1:
status = "Excellent (1) : The air quality is excellent. The air pollution pose no threat. The conditions ideal for outdoor activities.";
break;
case 2:
status = "Very Good (2) : Air quality is very good, and air pollution poses little or no risk. Conditions very good for outdoor activities";
break;
case 3:
status = "Moderate (3) : Air quality is acceptable. however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.";
break;
case 4:
status = "Satisfactory (4) : Members of sensitive groups may experience health effects, Other people should limit spending time outdoors, especially when they experience symptoms such as cough or sore throat.";
break;
case 5:
status = "Bad (5) : Everyone may begin to experience health effects, members of sensitive groups may experience more serious health effects. People at risk should avoid to go outside. Not recommended for outdoor activities.";
break;
case 6:
status = "Severe (6) : Air quality is severe. Everyone may experience more serious health effects. People at risk should be avoided to go outside and should limit the outdoor activities to minimum. Outdoor activities are discouraged.";
break;
case 7:
status = "Hazardous (7) : Health warnings of emergency conditions. People at risk should be avoided to go outside and should limit the outdoor activities to minimum. Outdoor activities are strongly discouraged.";
break;
default:
break;
}
}
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