An unreferenced variable in the source code of a computer program is a variable that is defined but which is never used. This may result in a harmless waste of memory. Many compilers detect such variables and do not allocate storage for them (i.e., "optimize away" their storage), generally also issuing a warning as they do.
Some coding guideline documents consider an unreferenced variable to be a symptom of a potential coding fault. On the other hand, unreferenced variables can be used as temporary placeholders to indicate further expected future developments in the code.
Examples
C:
int main(void) { int i, j; for (i=0; i<10; i++) printf("%d", i); return 0; }In this example, j is an unreferenced variable.
References
Blair-Chappell, Stephen; Stokes, Andrew (2012-04-19). Parallel Programming with Intel Parallel Studio XE. John Wiley & Sons. p. 108. ISBN 978-1-118-23488-4. 978-1-118-23488-4 ↩