array.rst

Arrays

Introduction

Supports arrays of simple types, such as char, int, double, or POD structures (i.e. basic C structures).

The Array is a class template, so requires an additional ElementType parameter:

#include <FlashString/Array.hpp>

DEFINE_FSTR_ARRAY(myDoubleArray, double,
   PI, 53.0, 100, 1e8, 47
);
Serial.print("My double array: ");
myDoubleArray.printTo(Serial);
Serial.println();

Note

Objects do not inherit from Printable because it is a virtual base class.

Therefore, statements like Serial.println(myDoubleArray) are not supported.

This also avoids ambiguity between implicit WString conversions.

There are some Print helper functions in the library you can use:

FSTR::println(Serial, myDoubleArray);

These are templated so will handle both simple data types and Objects.

You can share Arrays between translation units by declaring it in a header:

DECLARE_FSTR_ARRAY(table);

Tables

Simple tables can be implemented using Arrays, like this:

struct TableRow {
   float columns[3];

   int operator[](size_t index) const
   {
      return columns[index];
   }
};
DEFINE_FSTR_ARRAY(table, TableRow,
   {0.1, 0.2, 0.3},
   {0.6, 0.7, 0.8}
);
for(auto row: table) {
   Serial.printf("%f, %f, %f\n", row[0], row[1], row[2]);
}

Each row is a fixed size. The TableRow class template is provided to simplify this:

#include <FlashString/Table.hpp>

using FloatRow = FSTR::TableRow<float, 3>;
DEFINE_FSTR_ARRAY(table, FloatRow,
   {0.1, 0.2, 0.3},
   {0.6, 0.7, 0.8}
);
table.printTo(Serial);
table.println();

If you want to create a table with rows of different sizes or types, use a :doc:`Vector <vector>`.

Additional Macros

DEFINE_FSTR_ARRAY_DATA(name, ...)

Define the data structure without an associated reference.