print a 2d char array

Using Arduino Programming Questions
1

I have a question. I have a 2d char array and I want to print a port of it with Serial.println() in a function with a variable as arguement.

char (*text)[6] = { 
	{
		"configuring component\n"
		"1 = turnout\n"
		"2 = memory\n"
		"3 = detector"
	},{
		"select ID"
	},{
		"select IO"
	},{
		"Adjust curved switch position\n"
		"use 0-9, - and + to adjust the position\n"
		"send 's' if position is correct"
	},{
		"Adjust straight switch position\n"
		"use 0-9, - and + to adjust the position\n"
		"send 's' if position is correct"
	},{
		"press Y/n to store/discard the object"
	}
} ;

static void printState(byte i) {
        while(*text[i] != 0) {
	    Serial.write(*text[i]);
            *text[i]++; } } // N.B. I have not yet tried to compile this because reasons

I believe this might work but I have no clue to be honest. I am also not content with the while loop. I copied it from a function from work. But I should be able to use the Serial.print function.

I understand pointer to this extend. I am puzzled much by pointers to 2D arrays. Can anybody give me a hand with solving this puzzle?

2

What about a simple Serial.print(text[0]) :wink:

3

bask185:
I have a 2d char array ....

char (*text)[6] ;

No, you have an array of pointers to chars, that's a different beast.

Which type of Arduino are you using?

The strings reside in Flash and RAM , which is rather precious on smaller Arduinos.

4

Whandall:
No, you have an array of pointers to chars, that's a different beast.

OP doesn't even have that. If you drop his/her variable definition / initialization into a proper Arduino sketch, it won't compile:

char (*text)[6] = {
  {
    "configuring component\n"
    "1 = turnout\n"
    "2 = memory\n"
    "3 = detector"
  }, {
    "select ID"
  }, {
    "select IO"
  }, {
    "Adjust curved switch position\n"
    "use 0-9, - and + to adjust the position\n"
    "send 's' if position is correct"
  }, {
    "Adjust straight switch position\n"
    "use 0-9, - and + to adjust the position\n"
    "send 's' if position is correct"
  }, {
    "press Y/n to store/discard the object"
  }
};

void setup() {
}

void loop() {
}

Arduino: 1.8.5 (Windows 10), TD: 1.44, Board: "Arduino/Genuino Uno"

sketch_aug21b:22: error: scalar object 'text' requires one element in initializer

 };

 ^

exit status 1
scalar object 'text' requires one element in initializer

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.
5

Whandall:
No, you have an array of pointers to chars, that's a different beast.

Which type of Arduino are you using?

The strings reside in Flash and RAM , which is rather precious on smaller Arduinos.

O yeah, I forgot about that small detail. At work I program a thing with 32k RAM which is like 'unlimited variables space to us. We tried to fill it all, but we only reached 8k at most. At home I program an Uno.

So it's best to go back to simple Serial.println("with hard coded texts");

septillion:
What about a simple Serial.print(text[0]) :wink:

Makes perfect sense to me. That does the exact same thing as my while loop from my old print function.

6

I had the impression the brackets would not matter, but they do.

const char *text[6] = {
  "configuring component\n"
  "1 = turnout\n"
  "2 = memory\n"
  "3 = detector",
  
  "select ID",
  
  "select IO",
  
  "Adjust curved switch position\n"
  "use 0-9, - and + to adjust the position\n"
  "send 's' if position is correct",
  
  "Adjust straight switch position\n"
  "use 0-9, - and + to adjust the position\n"
  "send 's' if position is correct",
  
  "press Y/n to store/discard the object"
} ;

void printState(byte i) {
  Serial.print(text[i]);
}

void setup() {
  Serial.begin(250000);
  for (byte i=0; i<sizeof(text)/sizeof(text[0]); i++) {
    Serial.print(F("State "));
    Serial.print(i);
    Serial.print(F(" = \""));
    printState(i);
    Serial.println(F("\"\n"));
  }
}
void loop() {}

(the following was copied from the Serial monitor using ctrl-C :wink: )

State 0 = "configuring component
1 = turnout
2 = memory
3 = detector"

State 1 = "select ID"

State 2 = "select IO"

State 3 = "Adjust curved switch position
use 0-9, - and + to adjust the position
send 's' if position is correct"

State 4 = "Adjust straight switch position
use 0-9, - and + to adjust the position
send 's' if position is correct"

State 5 = "press Y/n to store/discard the object"
7 
char (*text)[6] = {

That is a pointer to an array of six characters. The parens cause the indirection to happen first.

char *text[6] = {

This is an array of six pointers to characters.

If you REALLY want a 2D array of characters, every row has to be the same length:

const char text[6][104] =