enum t_knownTypes : byte {INTEGER, CONST_CHAR_STAR, FLOAT};

struct t_var {
  const char * name;
  t_knownTypes type;
  void * varPtr;
};

int intVar = 3;
const char * someText = "Some Text";
float floatVar = 3.1415;

t_var variables[] = {
  {"intVar", INTEGER, &intVar},
  {"someText", CONST_CHAR_STAR, &someText},
  {"floatVar", FLOAT, &floatVar},
};


t_var * getInfoFor(const char * varName) {
  for (auto & v : variables)
    if (!strcmp(varName, v.name)) return &v;
  return nullptr;
}

void printVariable(const char * varName) {
  t_var * ptr = getInfoFor(varName);
  Serial.print(varName);
  Serial.print(F(" = ["));
  if (ptr) {
    switch (ptr->type) {
      case INTEGER: Serial.print(*((int*) ptr->varPtr)); break;
      case CONST_CHAR_STAR: Serial.print(*((const char **) ptr->varPtr)); break;
      case FLOAT: Serial.print(*((float*) ptr->varPtr)); break;
    }
    Serial.println(F("]"));
  } else Serial.println(F("unknown variable]"));
}

void setup() {
  Serial.begin(115200);
  printVariable("intVar");
  printVariable("someText");
  printVariable("floatVar");
  printVariable("does not exist");
}

void loop() {}