Add String object to character array in Arduino

Question

I am using Arduino. I would like to add a String object to an array of characters.

String msg = "ddeeff"

char charArr[1600];

//assume charArr already contains some string
//How can I do something like this to append String to charArray?
charArr = charArr + msg;

Answer 1

This will work for an Arduino String object.

strcat( charArr, msg.c_str() );

The String object is msgconverted to an array of characters using the String c_str () method. Then you can use strcat () to add 2 character arrays.

As Rakete1111 mentioned, undefined behavior if charArrnot large enough

Answer 2

Stringhas operator+, which takes const char*, and also has a function c_str()that converts it to const char*.

:

String temp = charrArr + msg; //Store result in a String

//Copy every character
std::strncpy(charArr, temp.c_str(), sizeof(charrArr));