Arduino：字符串连接？

发布于 2024-11-03 09:49:21 字数 601 浏览 3 评论 0原文

我正在尝试为 Arduino 编写一个 join 方法：

#define ARG_DELIMITER ','

  String join(const String strs[], const int len) {
    String result = "";
    for (int i = 0; i < len; i++) {
      result += strs[i] + ARG_DELIMITER;
      Serial.println(result);
    }
    return result.substring(0, result.length() - 1);
  }

loop() 中的调用代码：

const String args[3] = {"foo", "bar", "baz"};
Serial.println(SlaveTalk.join(args, 3));

这会打印以下内容：

foo
foo
foo
fo

只要程序运行，后跟空字符串。

我在这里做错了什么？

原文

I'm trying to write a join method for the Arduino:

#define ARG_DELIMITER ','

  String join(const String strs[], const int len) {
    String result = "";
    for (int i = 0; i < len; i++) {
      result += strs[i] + ARG_DELIMITER;
      Serial.println(result);
    }
    return result.substring(0, result.length() - 1);
  }

The calling code in loop():

const String args[3] = {"foo", "bar", "baz"};
Serial.println(SlaveTalk.join(args, 3));

This prints the following:

foo
foo
foo
fo

followed by empty strings as long as the program runs.

What am I doing wrong here?

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卖梦商人 2024-11-10 09:49:21

这一行

const String args[3] = {"foo", "bar", "baz"};

给出了字符串

"foo\0" "bar\0" "baz\0"

，其中 \0 是 NULL 字符。因此，当您连接时，我希望您最终会得到：

"foo\0bar\0baz\0"

打印在 null 处停止，这就是您看到 foo 3 次的原因。在 return 语句中，长度为 3“foo”，减去 1 得到“fo”

This line

const String args[3] = {"foo", "bar", "baz"};

gives you the strings

"foo\0" "bar\0" "baz\0"

where the \0 is the NULL character. So when you concat, I expect you're ending up with:

"foo\0bar\0baz\0"

The printing stops at the null which is why you see foo 3 times. In the return statement, the length is 3 "foo" and subtracting 1 gives you "fo"

回复收藏 0 原文

坏尐絯℡ 2024-11-10 09:49:21

以下代码使用 Arduino 软件版本 0022 和带有 ATmega 328 的 Arduino Duemilanove 按预期工作：

#define ARG_DELIMITER ','

class SlaveTalkClass
{
  public:
    String join(const String strs[], const int len) {
      String result = "";
      for (int i = 0; i < len; i++) {
        result += strs[i] + ARG_DELIMITER;
        Serial.println(result);
      }
      return result.substring(0, result.length() - 1);
    }
} SlaveTalk;

void setup()
{
  Serial.begin(9600);
}

void loop()
{
  const String args[3] = {"foo", "bar", "baz"};
  Serial.println(SlaveTalk.join(args, 3));
}

它会重复将以下内容打印到串行监视器：

foo,
foo,bar,
foo,bar,baz,
foo,bar,baz

The following code works as intended using the Arduino software version 0022 and an Arduino Duemilanove w/ ATmega 328:

#define ARG_DELIMITER ','

class SlaveTalkClass
{
  public:
    String join(const String strs[], const int len) {
      String result = "";
      for (int i = 0; i < len; i++) {
        result += strs[i] + ARG_DELIMITER;
        Serial.println(result);
      }
      return result.substring(0, result.length() - 1);
    }
} SlaveTalk;

void setup()
{
  Serial.begin(9600);
}

void loop()
{
  const String args[3] = {"foo", "bar", "baz"};
  Serial.println(SlaveTalk.join(args, 3));
}

It repeatedly prints the following to the Serial Monitor: