user48730: I have a string to be splitted into define chunks.
For example new_str="abcdefghjklmnopqrstuvwxyz, and my goal is to split it to chunks of split_size=5, so the result should be :abcde,fghij and so o.
new_str gets every time a different string.
split_size can be any size.
I have 2 questions:
1) Attached code does the job, but looks a BIT not elegant for a newbie like me. is there another way doing it ?
2)In code attached, output is Serial.println(tmp) and should be replaced with an output function to post each chunk to as a MQTT message. Ive rather that each chunk would be stored into a global array, to be sent later on in code out side msgSplitter.
So I wrote the following code:
int split_size=5;
char new_str[]="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
void setup() {

        Serial.begin(9600);
        Serial.print("String length: ");
        Serial.println(strlen(new_str));
        Serial.print("Split Size: ");
        Serial.println(strlen(split_size));

        msgSplitter(new_str, split_size, "Split #");

}
void msgSplitter( const char* msg_in, int chop_size, char *prefix){
        num=ceil((float)strlen(msg_in)/chop_size);
        char tmp[50];
        int pre_len;

        if (num > 1) {
                for (int k=0; k<num; k++) {
                  pre_len=0;
                        sprintf(tmp,"%s %d: ",prefix,k);
                        pre_len = strlen(tmp);
                        for (int i=0; i<chop_size; i++) {
                                tmp[i+pre_len]=(char)msg_in[i+k*chop_size];
                                tmp[i+1+pre_len]='\0';
                        }
                        Serial.println(tmp);
                }
        }
        else {
                Serial.println(msg_in);
        }
}


user37622: // concat version
void msgSplitter(const char* msg_in, int chop_size, char *prefix) {
  char tmp[50];
  int size = strlen(msg_in);
  for (int pos = 0, k = 0; pos < size; pos += chop_size) {
    int l = sprintf(tmp, "%s %d: ", prefix, k++);
    strncat(tmp + l, msg_in + pos, chop_size);
    Serial.println(tmp);
  }
}

// only value version
void msgSplitter(const char* msg_in, int chop_size, char *prefix) {
  char tmp[chop_size + 1];
  tmp[chop_size] = 0;
  int size = strlen(msg_in);
  for (int pos = 0; pos < size; pos += chop_size) {
    strncpy(tmp, msg_in + pos, chop_size);
    Serial.println(tmp);
  }
}


48730: <p>I have a string to be splitted into define chunks.</p>

<p>For example <code>new_str="abcdefghjklmnopqrstuvwxyz</code>, and my goal is to split it to chunks of <code>split_size=5</code>, so the result should be :<code>abcde</code>,<code>fghij</code> and so o.</p>

<p><code>new_str</code> gets every time a different string.</p>

<p><code>split_size</code> can be any size.</p>

<p>I have 2 questions:</p>

<p>1) Attached code does the job, but looks a BIT not elegant for a newbie like me. is there another way doing it ?</p>

<p>2)In code attached, output is <code>Serial.println(tmp)</code> and should be replaced with an output function to post each chunk to as a MQTT message. Ive rather that each chunk would be stored into a global array, to be sent later on in code out side <code>msgSplitter</code>.</p>

<p>So I wrote the following code:</p>

<pre><code>int split_size=5;
char new_str[]="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
void setup() {

        Serial.begin(9600);
        Serial.print("String length: ");
        Serial.println(strlen(new_str));
        Serial.print("Split Size: ");
        Serial.println(strlen(split_size));

        msgSplitter(new_str, split_size, "Split #");

}
void msgSplitter( const char* msg_in, int chop_size, char *prefix){
        num=ceil((float)strlen(msg_in)/chop_size);
        char tmp[50];
        int pre_len;

        if (num &gt; 1) {
                for (int k=0; k&lt;num; k++) {
                  pre_len=0;
                        sprintf(tmp,"%s %d: ",prefix,k);
                        pre_len = strlen(tmp);
                        for (int i=0; i&lt;chop_size; i++) {
                                tmp[i+pre_len]=(char)msg_in[i+k*chop_size];
                                tmp[i+1+pre_len]='\0';
                        }
                        Serial.println(tmp);
                }
        }
        else {
                Serial.println(msg_in);
        }
}
</code></pre>
 37622: <pre><code>// concat version
void msgSplitter(const char* msg_in, int chop_size, char *prefix) {
  char tmp[50];
  int size = strlen(msg_in);
  for (int pos = 0, k = 0; pos &lt; size; pos += chop_size) {
    int l = sprintf(tmp, "%s %d: ", prefix, k++);
    strncat(tmp + l, msg_in + pos, chop_size);
    Serial.println(tmp);
  }
}

// only value version
void msgSplitter(const char* msg_in, int chop_size, char *prefix) {
  char tmp[chop_size + 1];
  tmp[chop_size] = 0;
  int size = strlen(msg_in);
  for (int pos = 0; pos &lt; size; pos += chop_size) {
    strncpy(tmp, msg_in + pos, chop_size);
    Serial.println(tmp);
  }
}
</code></pre>
