从串行监视器读取和存储整数

Question

描述

我想了解如何在不使用Serial.parseInt()的情况下在变量中写入和存储整数。我找不到关于这方面的任何代码示例。也许这是正确的方法，虽然它不检测和大写字母和特殊字符。请留下一些关于改进方法的反馈意见。谢谢！)

void setup()
{
  Serial.begin(9600); // Opens serial port, sets data rate to 9600 bps
  Serial.println(F("Serial port opened!"));
}

void loop()
{
  byte received;
  static byte counter = 0;
  static uint32_t number = 0; // Store value from 0 to 4294967295

  while (Serial.available()) // Read data in serial receive buffer
  {
    received = Serial.read(); // Store received byte
    if (received != 10) // Terminate if newline char detected
    {
      if (counter != 0) // Put number in its correct position (base-10 system)
      {
        number *= 10;
        number += (received - '0');
      }
      else
      {
        number = (received - '0');
      }
      counter++;
    }
    else
    {
      Serial.println(number); // Print value inside number and reset
      counter = 0;
    }
  }
}

Answer 1

要获得更健壮的代码来检测非数字输入、溢出和启动阶段，请考虑使用状态机。

typedef struct {
  int counter;  // <0:indeterminate, 0:spacing, >0:digits; 
  uint32_t number;
} loop_state;

// Quietly drop data in 3 cases:
// 1) Overflow
// 2) Non-numeric
// 3) When state is indeterminate
void loop(loop_state *state) {
  while (Serial.available()) {
    byte received = Serial.read(); // Store received byte
    if (received >= '0' || received <= '9') { // or isdigit((unsigned char) received)
      if (state->counter >= 0) {
        state->counter++;
        unsigned digit = received - '0';
        if (state->number >= UINT32_MAX / 10
            && (state->number > UINT32_MAX / 10 || digit > UINT32_MAX % 10)) {
          // overflow
          state->counter = -1;
          continue;
        }
        state->number = state->number * 10 + digit;
      }
    } else if (isspace((unsigned char) received)) {
      if (state->counter == 1) {
        Serial.println(state->number);
      }
      state->number = 0;
      state->counter = 0;
    } else {
      state->number = 0;
      state->counter = -1;
    }
  }
}