Implicit conversion
Implicit conversion is an automatic change of a value from one type to another according to language rules, without an explicit conversion operation in the source code.
100 Java Mistakes and How to Avoid Them
Implicit conversion is an automatic type conversion performed by Java according to its conversion rules without an explicit cast or conversion call.
- How it is used
- Prevents expression, numeric, and generic-type bugs caused by Java conversions that occur without explicit casts.
- How deep it goes
- Explains conversion consequences through concatenation, conditional expressions, compound assignments, and erased generics, with avoidance guidance and inspection limits.
- Examples
- Uses `"Entry#" + index + 1`, `char c *= 1.2`, byte updates and shifts, and a `List<String>` read.
- What you can do after
- Diagnose/debug with it by spotting hidden string, numeric, and generic casts and choosing explicit safer alternatives.
Read how 100 Java Mistakes and How to Avoid Them explains implicit conversion →
100 C++ Mistakes and How to Avoid Them
An automatic conversion performed by C++ without an explicit cast or conversion request in the source code.
- How it is used
- Uses implicit conversion to explain hidden readability, correctness, and performance costs in class operations and legacy modernization.
- How deep it goes
- Explains conversion constructors, conversion operators, temporary construction, and explicit alternatives, but does not develop the full conversion-rule system.
- Examples
- Demonstrates Circle construction, Rational output and comparison, and Complex arithmetic that silently creates converted operands and temporaries.
- What you can do after
- Diagnose hidden conversions and reduce them with explicit constructors, named conversion functions, or type-specific operator overloads.
Read how 100 C++ Mistakes and How to Avoid Them explains implicit conversion →
Modern C, Third Edition
An implicit conversion is an automatic C conversion that changes a value from one type to another according to the language's conversion rules.
- How it is used
- Explains how C supplies required types for initialization, assignment, function arguments, and arithmetic expressions.
- How deep it goes
- Works through promotions and arithmetic rules, stopping short of a complete conversion table while flagging platform-dependent and precision-losing cases.
- Examples
- Uses integer and floating initializations, hexadecimal and decimal literals, mixed-sign comparisons, cosf, printf, and complex arithmetic.
- What you can do after
- Evaluate C expressions and conversions for preserved values, information loss, implementation-defined behavior, signedness hazards, and precision loss.
Read how Modern C, Third Edition explains implicit conversion →
Modern C
An implicit conversion is an automatic C conversion that changes a value from one type to another without an explicit cast.
- How it is used
- Uses automatic type changes to explain assignments, operators, comparisons, arithmetic, and restricted pointer interactions.
- How deep it goes
- Explains value fitting, literal typing, signedness, precision loss, implementation-defined results, and pointer restrictions through worked examples.
- Examples
- Uses typed initializations, hexadecimal literals, mixed-sign comparisons, pointer assignments, and byte inspection of an unsigned integer.
- What you can do after
- Evaluate conversion safety by checking value ranges, operand signedness, precision, pointer compatibility, and whether behavior is implementation-defined or undefined.
Related concepts
- narrowing conversionincludes · A narrowing conversion converts a value to a type with a smaller representable range or lower precision, potentially losing information.
- booleancontrasts with · A Boolean is a logical type or value representing truth or falsity, conventionally with two states: true and false.
- data conversioncontrasts with · Data conversion is the transformation of a value or data from one type, format, or representation to another, explicitly or implicitly.
- Kotlincontrasts with · Kotlin is a statically typed general-purpose programming language that targets the JVM and other platforms and interoperates with Java.
These guides are generated from the text of Manning books by Manning's knowledge graph and link to the sections they draw on. The full books are available on liveBook and at manning.com.