我在输入字符串/字符到串行监视器时遇到问题，而且我是编程的初学者，因此我不知道如何解决它。
我有一个if / else语句，就像switch case语句一样。我确实从一个开关盒开始，但我正在开发很多问题，一个是输入字符串/字符（A，S，M，D，P）指向每个案例。我知道一个switch case用于int，所以我放弃了并转移到多个if / else语句。
我试过（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”中的错误消息。功能。
这里是输入代码的使用（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，但是这会循环我的程序的开头并且不允许我输入值，或者它根本就没有取值。
任何帮助将不胜感激，我将在下面发布我的完整代码，以便您可以理解我的程序（if / else等问题位于顶部）。
*编辑：忘了提，我可以做点什么，
char theOperator = dataInput();
if (theOperator == 1) {
// If input is equal to 1, carry out function 'addition()'
addition();
}
这很有效。但是我希望它取代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);
}
}
答案 0 :(得分：0)
在char dataInput()函数中，您使用Serial.parseInt()进行串行输入，输入'A'时，parseInt将返回0.请参阅documentation。为了读取char，请使用Serial.read()来获取单个字符。
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;
}
}