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## 4.7 Promotion and Demotion of Data Types

Many operators and functions can work with mixed data types. For example

 ```uint8 (1) + 1 ⇒ 2 ```

where the above operator works with an 8-bit integer and a double precision value and returns an 8-bit integer value. Note that the type is demoted to an 8-bit integer, rather than promoted to a double precision value as might be expected. The reason is that if Octave promoted values in expressions like the above with all numerical constants would need to be explicitly cast to the appropriate data type like

 ```uint8 (1) + uint8 (1) ⇒ 2 ```

which becomes difficult for the user to apply uniformly and might allow hard to find bugs to be introduced. The same applies to single precision values where a mixed operation such as

 ```single (1) + 1 ⇒ 2 ```

returns a single precision value. The mixed operations that are valid and their returned data types are

 Mixed Operation Result double OP single single double OP integer integer double OP char double double OP logical double single OP integer integer single OP char single single OP logical single

The same logic applies to functions with mixed arguments such as

 ```min (single (1), 0) ⇒ 0 ```

where the returned value is single precision.

In the case of mixed type indexed assignments, the type is not changed. For example

 ```x = ones (2, 2); x (1, 1) = single (2) ⇒ x = 2 1 1 1 ```

where `x` remains of the double precision type.

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