The operators `+`, `-`, `*`, and `/` respectively evaluate to
the sum, difference, product, or quotient (respectively) of the two
operands. The operation is conducted using the data type of the
operands, so, for example, `9 / 4` gives `2` since 9 and 4 are
*int variables*.

This also means that the operation can overflow if the result is
larger than that which can be stored in the data type (e.g. adding 1
to an *int* with the value 2,147,483,647 gives
-2,147,483,648).

If the operands are of different types, the “larger” type is used for
the calculation. If one of the numbers (operands) are of the type
**float** or of type **double**, floating point math will be used for
the calculation.

Note

The specifics of these rules are beyond the scope of this documentation; for more information, see The C++ Programming Language, by Bjarne Stroustroup, Appendix C, especially §§C.4-C.6, or this WikiBooks entry on C++ type conversion.

Note

For more information on how computers represent integers, see the Wikipedia page on two’s complement.

result = value1 + value2; result = value1 - value2; result = value1 * value2; result = value1 / value2;

- Know that
*integer constants*default to*int*, so some constant calculations may overflow (e.g., 200000 * 5000000 will yield a negative result). - Choose variable sizes that are large enough to hold the largest results from your calculations.
- Know at what point your variable will “roll over” and also what happens in the other direction e.g. (0 - 1) for unsigned arithmetic, or (0 - -2,147,483,648) for signed arithmetic.
- For math that requires fractions, float variables may be used, but be aware of their drawbacks: large size and slow computation speeds (the STM32 has no floating point hardware, so all floating point calculations have to be done in software).
- Use cast operator, e.g.
`(int)myFloat`to convert one variable type to another on the fly.

Since the STM32 processor on the Maple is a 32-bit machine, the int
type overflows at a much higher value on Maple than on Arduino. In
particular, on Maple, ints do not overflow (become negative) until
they reach 2,147,483,648; on the Arduino, they overflow at 32,767.
Because of this, programs running on Maple are much less likely to run
into overflow issues. The following table summarizes the sizes and
ranges of integer datatypes on the Maple (the ranges of `long long`
types are approximate):

Datatype | Unsigned range | Signed range | Size (bytes) |
---|---|---|---|

char |
0 — 255 | -128 — 127 | 1 |

short |
0 — 65,535 | -32,768 — 32,767 | 2 |

int |
0 — 4,294,967,295 | -2,147,483,648 — 2,147,483,647 | 4 |

long |
0 — 4,294,967,295 | -2,147,483,648 — 2,147,483,647 | 4 |

long long |
0 — 1.8*10^{19} (approx.) |
-9.2*10^{18} — 9.2*10^{18} (approx.) |
8 |

- The individual sizes (in bits) of various available types are
defined in
*libmaple_types.h*. *sizeof*()

License and Attribution

Portions of this page were adapted from the Arduino Reference Documentation, which is released under a Creative Commons Attribution-ShareAlike 3.0 License.