Some programming languages allow compilers to provide coercion others require it. Implicit type conversion, also known as coercion or type juggling, is an automatic type conversion by the compiler. C-like languages Implicit type conversion More important is the multitude of ways and rules that apply to what data type (or class) is located by a pointer and how a pointer may be adjusted by the compiler in cases like object (class) inheritance.Įxplicit casting in various languages Ada Īda provides a generic library function Unchecked_Conversion. In the C family of languages and ALGOL 68, the word cast typically refers to an explicit type conversion (as opposed to an implicit conversion), causing some ambiguity about whether this is a re-interpretation of a bit-pattern or a real data representation conversion. Because the stored bits are never changed, the programmer must know low level details such as representation format, byte order, and alignment needs, to meaningfully cast. For example, 32 contiguous bits may be treated as an array of 32 booleans, a 4-byte string, an unsigned 32-bit integer or an IEEE single precision floating point value. The word cast, on the other hand, refers to explicitly changing the interpretation of the bit pattern representing a value from one type to another. The storage needs may change as a result of the conversion, including a possible loss of precision or truncation. In these languages, conversion refers to either implicitly or explicitly changing a value from one data type storage format to another, e.g. In most ALGOL-like languages, such as Pascal, Modula-2, Ada and Delphi, conversion and casting are distinctly different concepts. adding type identifiers or calling built-in routines) or by coding conversion routines for the compiler to use when it otherwise would halt with a type mismatch.
#VB AUTO CONVERT STRING TO LONG CODE#
Explicit type conversions are either indicated by writing additional code (e.g. For example, in an expression mixing integer and floating point numbers (like 5 + 0.1), the compiler will automatically convert integer representation into floating point representation so fractions are not lost. In most languages, the word coercion is used to denote an implicit conversion, either during compilation or during run time. Weak typing language often allow forcing the compiler to arbitrarily interpret a data item as having different representations-this can be a non-obvious programming error, or a technical method to directly deal with underlying hardware.
Languages with strong typing typically do little implicit conversion and discourage the reinterpretation of representations, while languages with weak typing perform many implicit conversions between data types. In general, both primitive and compound data types can be converted.Įach programming language has its own rules on how types can be converted. Two important aspects of a type conversion are whether it happens implicitly (automatically) or explicitly, and whether the underlying data representation is converted from one representation into another, or a given representation is merely reinterpreted as the representation of another data type. Type conversions can take advantage of certain features of type hierarchies or data representations. An example would be the conversion of an integer value into a floating point value or its textual representation as a string, and vice versa. In computer science, type conversion, type casting, type coercion, and type juggling are different ways of changing an expression from one data type to another. ( Learn how and when to remove this template message) ( May 2018) ( Learn how and when to remove this template message) Statements consisting only of original research should be removed. Please improve it by verifying the claims made and adding inline citations. This article possibly contains original research.
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