(also unreachable code)
Dead code definition
Dead code is programming that will never be executed during a program’s runtime and thus serves no purpose in the program’s functionality. In some cases, dead code can also refer to redundant code that may be executed during a program’s runtime, but would have no impact on its processes or outputs.
See also: code management
Causes of dead code
- The code may contain logic errors, such as incorrect conditional statements or loops, that prevent certain parts of the code from ever being executed.
- In some cases, code might be placed after a return statement or within an if block whose condition will always evaluate to false, making it unreachable.
- The developers may include variables, constants, functions, methods in the code at some stage that ultimately becomes unnecessary.
Damage caused by dead code
- Code clutter: Dead code makes it more difficult to understand and maintain the program’s codebase. For example, dead code may describe a feature that the program simply does not have, prompting additional reviews of the code to uncover the problem.
- Memory usage: In situations where dead code refers to redundant programming, running dead code consumes memory resources without adding any value.
- Storage and execution: Dead code increases the size of the program without affecting its operations. This extra size results in wasted storage space and possible problems when trying to run the program in low-memory environments.