Ada Programming/Keywords/delta

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Contents 1 Description 2 Example 3 See also 3.1 Wikibook 3.2 Ada Reference Manual 3.3 Ada Quality and Style Guide

[edit] Description

This keyword is used in the declaration of fixed point types. Delta represents the absolute error bound of a fixed point type; that is, delta gives a hint to the compiler how to choose the smallest incremental value of the type, called the Small of the type. This Small value is accessible via the attribute T'Small.

For Ordinary fixed point types, it is by default a power of two not greater than the delta; it is specifyable by an attribute clause to be any value not greater than the delta.

For decimal fixed point types, the Small value is equal to the delta, which of course must be a power of ten.

[edit] Example

type Fixed_Point is delta 0.01 digits 10;  -- A decimal fixed point type
My_Fixed_Point : Fixed_Point := 0.0;
...
My_Fixed_Point := 0.1;   -- Ok
My_Fixed_Point := 0.02;  -- Ok
My_Fixed_Point := 0.001; -- Oops - this value is too small.
                         -- It will be represented by zero.

[edit] See also

[edit] Wikibook

• Ada Programming
• Ada Programming/Keywords

[edit] Ada Reference Manual

• 2.9 Reserved Words (Annotated)
• Annex P (informative) Syntax Summary (Annotated)

[edit] Ada Quality and Style Guide

• 3.1.3 Capitalization

Ada Keywords

abort else new return abs elsif not reverse abstract (Ada 95) end null accept entry select access exception of separate aliased (Ada 95) exit or subtype all others synchronized (Ada 2005) and for out array function overriding (Ada 2005) tagged (Ada 95) at task generic package terminate begin goto pragma then body private type if procedure case in protected (Ada 95) until (Ada 95) constant interface (Ada 2005) use is raise declare range when delay limited record while delta loop rem with digits renames do mod requeue (Ada 95) xor