Question

________ variables are useful for establishing two-way communication between modules.

A ) Value
B ) Constant
C ) Reference
D ) I/O
E ) None of these

Answer 1

Reference variables are key to two-way communication between modules as changes to parameters passed by reference affect the original variable. Unlike constant and value variables, references pass the address allowing modifications in one module to impact another.

Step-by-step explanation:

Reference variables are useful for establishing two-way communication between modules. When you pass a parameter by reference, any changes made to the parameter in the called module are reflected in the calling module because it is the reference (or address) of the variable that is passed, not its value.

This stands in contrast to value variables, which pass a copy of the value and thus any changes made to the parameter within the called function do not affect the original variable. Constants are fixed values that do not change during the execution of a program, and thus cannot facilitate a two-way communication. The use of I/O (input/output) variables may seem like a possible answer, but typically these are not used for two-way communication between modules in the context of passing parameters.