将单个字符串/字符输入串行监视器
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【中文标题】将单个字符串/字符输入串行监视器【英文标题】：Inputting a single String/Char into Serial Monitor 【发布时间】：2017-08-16 00:09:15 【问题描述】：我在将字符串/字符输入串行监视器时遇到问题，我是编程初学者，因此不知道如何解决。
我有一个 if/else 语句，它的作用类似于 switch case 语句。我确实从一个 switch case 开始，但我遇到了很多问题，其中一个是输入一个字符串/字符（A、S、M、D、P）来指向每个 case。我知道 switch case 是针对 int 的，所以我放弃了，转而使用多个 if/else 语句。
我已经尝试过（在 void loop() 中），
char theOperator = dataInput();
if (theOperator == 'A')
// If input is equal to 1, carry out function 'addition()'
addition();
但它会显示我在“添加”函数中的错误消息。
这里是使用输入代码的地方（全局定义），
char theOperator;
char dataInput()
while (!Serial.available())
// Wait for the user to enter value
return Serial.parseInt();
我尝试过类似 Serial.read() 之类的东西，但这要么循环我的程序的开头并且不允许我输入值，要么根本不接受值。
任何帮助将不胜感激，我将在下面发布我的完整代码，以便您了解我的程序（if/else 等问题在顶部）。
*编辑：忘了说，我可以做类似的事情，
char theOperator = dataInput();
if (theOperator == 1)
// If input is equal to 1, carry out function 'addition()'
addition();
这很有效。但是我希望它取 A、S、M、D 或 P 而不是 1、2、3、4、5。
#define LED_RED 5
#define LED_ORANGE 6
#define LED_YELLOW 9
#define LED_GREEN 10
#define LED_BLUE 11
int potValue;
#define potPin A0
// Limits the range of the numbers entered to between -99 and 999
long firstNumber = constrain(firstNumber, -99, 999);
long secondNumber = constrain(secondNumber, -99, 999);
long value;
char theOperator;
char dataInput()
while (!Serial.available())
// Wait for the user to enter value
return Serial.parseInt();
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void setup()
Serial.begin(9600);
pinMode(LED_RED, OUTPUT);
pinMode(LED_ORANGE, OUTPUT);
pinMode(LED_YELLOW, OUTPUT);
pinMode(LED_GREEN, OUTPUT);
pinMode(LED_BLUE, OUTPUT);
pinMode(potPin, INPUT);
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void loop()
Serial.println ("Enter your chosen operator");
Serial.println ("A for Addition, S for Subtraction, M for Multiplication,");
Serial.println ("D for Division, and P for Potentiometer: ");
// Takes an input from the user
char theOperator = dataInput();
if (theOperator == 'A')
// If input is equal to 1, carry out function 'addition()'
addition();
else if (theOperator == 'S')
// If input is equal to 2, carry out function 'subtraction()'
subtraction();
else if (theOperator == 'M')
// If input is equal to 3, carry out function 'multiplication()'
multiplication();
else if (theOperator == 'D')
// If input is equal to 4, carry out function 'division()'
division();
else if (theOperator == 'P')
// If input is equal to 5, carry out function 'potentiometer()'
potentiometer();
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void addition()
Serial.println ("A");
Serial.println ("Please enter first number in format nnn: ");
firstNumber = dataInput(); // Asks the user to input the first set of numbers
/* Message must be in format cnnnnnn
therefore first number must be greater than or equal to -99 and less than or equal to 999*/
if (firstNumber >= -99 && firstNumber <= 999)
Serial.println (firstNumber); // Prints the first set of numbers for the user to view
else
/* If the data input does not match the format cnnnnnn then this error message will display
if the input is invalid the red LED will also turn on */
digitalWrite(LED_RED, HIGH);
Serial.println ("--------------- ERROR ---------------");
Serial.println ("Please enter second number in format nnn: ");
secondNumber = dataInput(); // Asks the user to input the second set of numbers
/* Message must be in format cnnnnnn
therefore second number must be greater than or equal to -99 and less than or equal to 999*/
if (secondNumber >= -99 && secondNumber <= 999)
// The LED will turn off if it was previously on because this is a valid input
digitalWrite(LED_RED, LOW);
Serial.println (secondNumber); // Prints the second set of numbers for the user to view
else
digitalWrite(LED_RED, HIGH);
Serial.println ("--------------- ERROR ---------------");
/* Give time for the red error LED to stay on
for the user to notice he/she has made an invalid input */
delay(500);
digitalWrite(LED_RED, LOW);
// As this case is for addition, it will add the first and second numbers
value = (firstNumber + secondNumber);
Serial.print("Value: ");
// Prints the value of the two sets of numbers so that the user can see the value of their message
Serial.println(value);
/////// The 'sign' flag ///////
if (value >= 1)
// If value is a positive number (excluding 0) turn orange LED on
digitalWrite(LED_ORANGE, HIGH);
else if (value <= -1)
// If value is a negative number, turn orange LED off
digitalWrite(LED_ORANGE, LOW);
else if (value == 0)
// If value is equal to 0, set orange LED at half brightness
int brightness;
// Changes the brightness of the LED so that it is half bright
brightness++;
brightness %= 128;
analogWrite(LED_ORANGE, brightness);
/////// The 'even' flag ///////
if ((value % 2) == 0)
// If the modulo is equal to 0, it's an even
digitalWrite(LED_BLUE, HIGH);
else
// If the modulo is not equal to 0, it's an odd
digitalWrite(LED_BLUE, LOW);
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void subtraction()
Serial.println ("S");
Serial.println ("Please enter the first number in format nnn: ");
firstNumber = dataInput();
/* Message must be in format cnnnnnn
therefore first number must be greater than or equal to -99 and less than or equal to 999*/
if (firstNumber >= -99 && firstNumber <= 999)
Serial.println (firstNumber); // Prints the first set of numbers for the user to view
else
/* If the data input does not match the format cnnnnnn then this error message will display
if the input is invalid the red LED will also turn on */
digitalWrite(LED_RED, HIGH);
Serial.println ("--------------- ERROR ---------------");
Serial.println ("Please enter second number in format nnn: ");
secondNumber = dataInput();
/* Message must be in format cnnnnnn
therefore second number must be greater than or equal to -99 and less than or equal to 999*/
if (secondNumber >= -99 && secondNumber <= 999)
digitalWrite(LED_RED, LOW);
Serial.println (secondNumber); // Prints the second set of numbers for the user to view
else
digitalWrite(LED_RED, HIGH);
Serial.println ("--------------- ERROR ---------------");
/* Give time for the red error LED to stay on
for the user to notice he/she has made an invalid input */
delay(500);
digitalWrite(LED_RED, LOW);
// As this case is for subtraction, it will subtract the first and second numbers
value = (firstNumber - secondNumber);
Serial.print("Value: ");
// Prints the value of the two sets of numbers so that the user can see the value of their message
Serial.println(value);
/////// The 'sign' flag ///////
if (value >= 1)
// If value is a positive number (excluding 0) turn orange LED on
digitalWrite(LED_ORANGE, HIGH);
else if (value <= -1)
// If value is a negative number, turn orange LED off
digitalWrite(LED_ORANGE, LOW);
else if (value == 0)
// If value is equal to 0, set orange LED at half brightness
int brightness;
// Changes the brightness of the LED so that it is half bright
brightness++;
brightness %= 128;
analogWrite(LED_ORANGE, brightness);
/////// The 'even' flag ///////
if ((value % 2) == 0)
// If the modulo is equal to 0, it's an even
digitalWrite(LED_BLUE, HIGH);
else
// If the modulo is not equal to 0, it's an odd
digitalWrite(LED_BLUE, LOW);
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void multiplication()
Serial.println ("M");
Serial.println ("Please enter the first number in format nnn: ");
firstNumber = dataInput();
/* Message must be in format cnnnnnn
therefore first number must be greater than or equal to -99 and less than or equal to 999*/
if (firstNumber >= -99 && firstNumber <= 999)
Serial.println (firstNumber); // Prints the first set of numbers for the user to view
else
/* If the data input does not match the format cnnnnnn then this error message will display
if the input is invalid the red LED will also turn on */
digitalWrite(LED_RED, HIGH);
Serial.println ("--------------- ERROR ---------------");
Serial.println ("Please enter second number in format nnn: ");
secondNumber = dataInput();
/* Message must be in format cnnnnnn
therefore second number must be greater than or equal to -99 and less than or equal to 999*/
if (secondNumber >= -99 && secondNumber <= 999)
digitalWrite(LED_RED, LOW);
Serial.println (secondNumber); // Prints the second set of numbers for the user to view
else
digitalWrite(LED_RED, HIGH);
Serial.println ("--------------- ERROR ---------------");
/* Give time for the red error LED to stay on
for the user to notice he/she has made an invalid input */
delay(500);
digitalWrite(LED_RED, LOW);
// As this case is for multiplication, it will multiply the first and second numbers
value = (firstNumber * secondNumber);
Serial.print("Value: ");
// Prints the value of the two sets of numbers so that the user can see the value of their message
Serial.println(value);
/////// The 'sign' flag ///////
if (value >= 1)
// If value is a positive number (excluding 0) turn orange LED on
digitalWrite(LED_ORANGE, HIGH);
else if (value <= -1)
// If value is a negative number, turn orange LED off
digitalWrite(LED_ORANGE, LOW);
else if (value == 0)
// If value is equal to 0, set orange LED at half brightness
int brightness;
// Changes the brightness of the LED so that it is half bright
brightness++;
brightness %= 128;
analogWrite(LED_ORANGE, brightness);
/////// The 'even' flag ///////
if ((value % 2) == 0)
// If the modulo is equal to 0, it's an even
digitalWrite(LED_BLUE, HIGH);
else
// If the modulo is not equal to 0, it's an odd
digitalWrite(LED_BLUE, LOW);
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void division()
Serial.println ("D");
Serial.println ("Please enter the first number in format nnn: ");
firstNumber = dataInput();
/* Message must be in format cnnnnnn
therefore first number must be greater than or equal to -99 and less than or equal to 999
Division by 0 is not allowed */
if (firstNumber >= -99 && firstNumber <= 999 && firstNumber != 0)
Serial.println (firstNumber); // Prints the first set of numbers for the user to view
else if (firstNumber == 0)
/* If the data input does not match the format cnnnnnn or if the input is
equal to 0 then this error message will display, and if the input is invalid
the red LED will also turn on, or if the input equals to 0 the LED will flash
and stay on at half brightness */
blinkError();
Serial.println ("--------------- ERROR ---------------");
else
digitalWrite(LED_RED, HIGH);
Serial.println ("Please enter second number in format nnn: ");
secondNumber = dataInput();
/* Message must be in format cnnnnnn
therefore second number must be greater than or equal to -99 and less than or equal to 999
Division by 0 is not allowed */
if (secondNumber >= -99 && secondNumber <= 999 && secondNumber != 0)
digitalWrite(LED_RED, LOW);
Serial.println (secondNumber); // Prints the second set of numbers for the user to view
else if (secondNumber == 0)
blinkError();
Serial.println ("--------------- ERROR ---------------");
else
digitalWrite(LED_RED, HIGH);
Serial.println ("--------------- ERROR ---------------");
/* Give time for the red error LED to stay on
for the user to notice he/she has made an invalid input */
delay(500);
digitalWrite(LED_RED, LOW);
// As this case is for division, it will divide the first and second numbers
value = (firstNumber / secondNumber);
Serial.print("Value: ");
// Prints the value of the two sets of numbers so that the user can see the value of their message
Serial.println(value);
/////// The 'sign' flag ///////
if (value >= 1)
// If value is a positive number (excluding 0) turn orange LED on
digitalWrite(LED_ORANGE, HIGH);
else if (value <= -1)
// If value is a negative number, turn orange LED off
digitalWrite(LED_ORANGE, LOW);
else if (value == 0)
// If value is equal to 0, set orange LED at half brightness
int brightness;
// Changes the brightness of the LED so that it is half bright
brightness++;
brightness %= 128;
analogWrite(LED_ORANGE, brightness);
/////// The 'even' flag ///////
if ((value % 2) == 0)
// If the modulo is equal to 0, it's an even
digitalWrite(LED_BLUE, HIGH);
else
// If the modulo is not equal to 0, it's an odd
digitalWrite(LED_BLUE, LOW);
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void potentiometer()
Serial.println("P");
do
if (potValue >= 0 && potValue <= 6)
/* If the value on the potentiometer is greater than or equal to 0,
or less than or equal to 6, the red LED will turn on */
potValue = analogRead(potPin); // Reads the value on the pin
potValue = map(potValue, 0, 1023, 0, 31); // Changes the default range from 0 to 1023 to 0 to 31
// Converts the DEC value of the potentiometer to BIN
Serial.println(potValue, BIN);
delay(500);
digitalWrite(LED_RED, HIGH);
digitalWrite(LED_ORANGE, LOW);
digitalWrite(LED_YELLOW, LOW);
digitalWrite(LED_GREEN, LOW);
digitalWrite(LED_BLUE, LOW);
else if (potValue >= 7 && potValue <= 12)
/* If the value on the potentiometer is greater than or equal to 3,
or less than or equal to 12, the orange LED will turn on */
potValue = analogRead(potPin); // Reads the value on the pin
potValue = map(potValue, 0, 1023, 0, 31); // Changes the default range from 0 to 1023 to 0 to 31
Serial.println(potValue, BIN);
delay(500);
digitalWrite(LED_RED, LOW);
digitalWrite(LED_ORANGE, HIGH);
digitalWrite(LED_YELLOW, LOW);
digitalWrite(LED_GREEN, LOW);
digitalWrite(LED_BLUE, LOW);
else if (potValue >= 13 && potValue <= 18)
/* If the value on the potentiometer is greater than or equal to 13,
or less than or equal to 18, the yellow LED will turn on */
potValue = analogRead(potPin); // Reads the value on the pin
potValue = map(potValue, 0, 1023, 0, 31); // Changes the default range from 0 to 1023 to 0 to 31
Serial.println(potValue, BIN);
delay(500);
digitalWrite(LED_RED, LOW);
digitalWrite(LED_ORANGE, LOW);
digitalWrite(LED_YELLOW, HIGH);
digitalWrite(LED_GREEN, LOW);
digitalWrite(LED_BLUE, LOW);
else if (potValue >= 19 && potValue <= 24)
/* If the value on the potentiometer is greater than or equal to 19,
or less than or equal to 24, the green LED will turn on */
potValue = analogRead(potPin); // Reads the value on the pin
potValue = map(potValue, 0, 1023, 0, 31); // Changes the default range from 0 to 1023 to 0 to 31
Serial.println(potValue, BIN);
delay(500);
digitalWrite(LED_RED, LOW);
digitalWrite(LED_ORANGE, LOW);
digitalWrite(LED_YELLOW, LOW);
digitalWrite(LED_GREEN, HIGH);
digitalWrite(LED_BLUE, LOW);
else if (potValue >= 25 && potValue <= 31)
/*If the value on the potentiometer is greater than or equal to 25,
or less than or equal to 31, the blue LED will turn on */
potValue = analogRead(potPin); // Reads the value on the pin
potValue = map(potValue, 0, 1023, 0, 31); // Changes the default range from 0 to 1023 to 0 to 31
Serial.println(potValue, BIN);
delay(500);
digitalWrite(LED_RED, LOW);
digitalWrite(LED_ORANGE, LOW);
digitalWrite(LED_YELLOW, LOW);
digitalWrite(LED_GREEN, LOW);
digitalWrite(LED_BLUE, HIGH);
while (true);
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void blinkError()
/////// The 'error' flag ///////
int brightness = 0;
// The for loop will loop 5 times
for (int x = 0; x < 5; x++)
digitalWrite(LED_RED, HIGH);
delay(100);
digitalWrite(LED_RED, LOW);
delay(100);
// Changes the brightness of the LED so that it is half bright
brightness++;
brightness %= 128;
analogWrite(LED_RED, brightness);
【问题讨论】：
如何输入？你看到了什么错误信息？ 我正在使用 arduino 和 arduino IDE。当我打开串行监视器时，它要求用户输入 A、S、M、D 或 P。当我当前输入 A 时，它会输出错误消息--------ERROR----- - 我在每个功能中都有，然后要求用户再次输入。如果我将它保留在 1、2、3、4、5 它可以工作，然后继续要求用户输入第一个数字等。我希望它接受字符串输入，但我已经尝试过了，但由于某种原因无法做到. 【参考方案1】：在您的char dataInput() 函数中，您使用Serial.parseInt() 进行串行输入，当输入'A' parseInt 时将返回0。请参阅documentation。要读取字符，请使用 Serial.read() 获取单个字符。
void loop()
Serial.println ("Enter your chosen operator");
Serial.println ("A for Addition, S for Subtraction, M for Multiplication,");
Serial.println ("D for Division, and P for Potentiometer: ");
// Takes an input from the user
char theOperator = Serial.read();
switch(theOperator)
case 'A':
// If input is equal to 1, carry out function 'addition()'
addition();
break;
case 'S':
// If input is equal to 2, carry out function 'subtraction()'
subtraction();
break;
case 'M':
// If input is equal to 3, carry out function 'multiplication()'
multiplication();
break;
case 'D':
// If input is equal to 4, carry out function 'division()'
division();
break;
case 'P':
// If input is equal to 5, carry out function 'potentiometer()'
potentiometer();
break;
【讨论】：
我已将 Serial.parseInt() 更改为 Serial.read() 并离开 theOperator = dataInput();因为如果我在循环中将 dataInput() 更改为 Serial.read() 或按照全局定义，它只会循环“输入您选择的运算符”并且不允许我输入。但是，如果我将其保留为 dataInput()，我可以输入 A、S、M、D 和 P，但是当我随后输入第一个数字时，它会输出奇怪的值，例如 1 是 49，而 123 是---- -ERROR----- 并添加这两个并输出 98？我很困惑。 不要改变数据输入，只改变循环中读取的字符。 我不太明白我要改变什么以上是关于将单个字符串/字符输入串行监视器的主要内容，如果未能解决你的问题，请参考以下文章
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