Arduino split char* based on delimiter to value - c++

Question

thanks for your time, so I have a Char* from mqtt
I want to break this down into 3 seperate values
Char* mqttvalue
//Input Would be like the below for example.
mqttvalue = (255,200,230);
// I would like to split the values into the below.
int 1 = 255
int 2 = 200
int 3 = 230
I've tried strtok with no luck. probably something really dumb but some guidance would help.
Thank you
Edit, what I tried.
//Dummy Value for testing
Split("255,240,230");
//Split Value
void Split(char* e) {
String v[3];
char *p;
int i = 0;
p = strtok(e, ",");
while(p && i < 3)
{
v[i] = p;
p = strtok(NULL, ",");
Serial.println(p);
++i;
};
Serial.println(v[0]);
Serial.println(v[1]);
Serial.println(v[2]);
}

Answer 1

Updated the code to the below from a string to char* its all now working.
//Split Value
void Split(char* e) {
char* v[3];
char *p;
int i = 0;
p = strtok(rgb, ",");
while(p && i < 3)
{
v[i] = p;
p = strtok(NULL, ",");
i++;
};
Serial.println(v[0]);
Serial.println(v[1]);
Serial.println(v[2]);
};

Answer 2

As this is quite often asked question and I'd propose more like using wrapper class inheriting Stream interface on C string (and it can be initialized from Arduino String object too).
However usage with Arduino String class is tricky as the original String shouldn't be altered during usage of StringStream, but it's possible to reinitialize it again. Using rvalue (String literal, passed into the class) is forbidden by using non const reference as the parameter of setData method and constructor.
However it's not tested much, so there might be some mistakes. The copy/move constructor and assigment is ommited (and it shouldn't be :D), also using operator=(String&) and operator=(const char*) would be more intuitive interface for it.
class StringStream : public Stream
{
public:
StringStream()
{
setTimeout(1);
}
StringStream(const char * str)
{
setData(str);
}
StringStream(const char * begin, const char * end)
{
setData(begin, end);
}
explicit StringStream(String & view) // cannot be String literal (rvalue) and it gets invalidated if you change original String
{
setData(view);
}
////////////////////////////////////
inline void setData(const char * begin, const char * end)
{
m_start = begin;
m_end = end;
setTimeout(1);
}
inline void setData(const char * begin)
{
setData(begin, begin + strlen(begin));
}
inline void setData(String & view)
{
setData(view.c_str(), m_start + view.length());
}
//////////////////////////////////
// Stream Interface:
virtual int available() override
{
return m_end - m_start;
}
virtual int read() override
{
if (m_start < m_end)
{
return *(m_start++);
}
return -1;
}
virtual int peek() override
{
if (m_start < m_end)
{
return *m_start;
}
return -1;
}
virtual size_t write(uint8_t) override {
return 0;
}
protected:
const char * m_start{0};
const char * m_end{0};
};
And the test program would be like:
void setup() {
Serial.begin(115200);
}
void loop() {
Serial.println("Output:");
StringStream test{" 144, 7899, -5478"};
Serial.println(test.parseInt());
Serial.println(test.parseInt());
Serial.println(test.parseInt());
test.setData("1 2");
Serial.println(test.parseInt());
Serial.println(test.parseInt());
delay(2000);
}