Pointers

Projects Programming
1

Hi there

I have been looking at this for a while and I am just confused. I know it is some sort of problem with pointers but dont know how to solve it.

I have a function which I call which returns a String up to 60 chars long. The first char is a "*" and the last a "!". Commas separate different values inside the string. I have not completed the data handling part ie there are still more variables to add/extract from the string but this is my starting point. The problem I have is that I keep getting the following error -

"cannot convert 'String' to 'char*' for argument '1' to 'char* strok(char*, const char*)'"

I assume that there is some problem relating to pointers which the initial of where I begin to extract the data.

David

String pageValue = connectAndRead();

  humiditytemp = atof(strtok(pageValue, "*"));
  humidity = atoi(strtok(NULL, ","));
  dewpoint = atof(strtok(NULL, ","));
  pressure = atof(strtok(NULL, ","));
  lightlevel = atof(strtok(NULL, ","));
2

  1. Do NOT use the class String on the arduino's. Search this forum for threads on the topic.

  2. atoi() etc expect array of char / char* not the class String and there is not built in cast for this.

  3. String is a class, array of char is a string (lower case). Lower case string is not the same as Upper case String.

Mark

3

There doesn't seem to be any error handling in that code, so if you ever encounter a malformed string I suspect you're going to crash and burn.