Store hex value as string (Arduino project)

Question

I'm working on an Arduino project and I want to store a hex value as string.

eg: Hex is C697C63B

for (byte i = 0; i < bufferSize; i++) {
     Serial.print(buffer[i], HEX);
}

I would like to store the String as x = "C697C63B";

  String CardID = "";
  for (byte i = 0; i < bufferSize; i++) {
    CardID += (buffer[i],HEX);
    Serial.println(CardID);
  }

But the Sting is stored as CardID = 16161616

Sorry I just start C++ for a week and I spend 3 day already just to find answer.

Okay i found the answer now thank you everyone that help

  String CardID = "";
  for (byte i = 0; i < bufferSize; i++)
    CardID += String(buffer[i], HEX);
  Serial.print(CardID);

`CardID += (buffer[i],HEX);` doesn't do what you think it does. Read up on [comma operator](http://stackoverflow.com/questions/54142/how-does-the-comma-operator-work). In addition, you need to provide [mcve]. — Algirdas Preidžius, Mar 17 '16 at 11:11

score 2 · Accepted Answer · answered Mar 17 '16 at 11:18

2

You should use an ostringstream:

auto outstr = std::ostringstream{};
outstr << std::hex << 0xC697C63Bul;
auto myHexString = outstr.str();

answered Mar 17 '16 at 11:18

cdonat

2,748
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sorry this **ostringstream** don't work in my arduino project do you have another idea? – user1437099 Mar 17 '16 at 11:29
1

@user1437099 You probably missed to add `#include `? See here: http://stackoverflow.com/a/9850537/1879699 – Andreas Mar 17 '16 at 11:39
already try #include #include #include #include but it can't – user1437099 Mar 17 '16 at 11:43
1

Doesn't your environment include a complete C++ standard library? – cdonat Mar 17 '16 at 12:29

score 0 · Answer 2 · answered Mar 17 '16 at 11:18

0

std::ostringstream + IO manipulator hex may be want you want.

answered Mar 17 '16 at 11:18

Youka

2,646
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sorry this **ostringstream** don't work in my arduino project do you have another idea? – user1437099 Mar 17 '16 at 11:34

score 0 · Answer 3 · answered Mar 17 '16 at 11:45

0

You can use c-style sprintf :

char str[100];
sprintf(str, "%08x", HEX);

answered Mar 17 '16 at 11:45

taarraas

1,483
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score 0 · Answer 4 · answered Mar 17 '16 at 11:50

0

#include <stdio.h>

int main(void) {
  int nHex = 0xC697C63B;
  char pHexStr[100];
  sprintf(pHexStr,"%x",nHex);
  fprintf(stdout, "%s", pHexStr);

  return 0;
}

answered Mar 17 '16 at 11:50

fandyushin

2,350
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score 0 · Answer 5 · answered Jun 21 '18 at 12:03

0

So simple in Arduino Programming Language to convert hex to be a string.

Just doing:

char StringValue[ ]=String(0xFF,HEX)

answered Jun 21 '18 at 12:03

Hzzkygcs

1,532
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Using ESP32, I receive a "array must be initialized with a brace-enclosed initializer" error message on compile. – Will Lovett Jun 24 '20 at 13:35

Store hex value as string (Arduino project)

5 Answers5