Question

Software coupling involves dependencies among pieces of software called modules. Which of the following are correct statements with respect to module coupling?

P: Common coupling occurs when two modules share the same global data.

Q: Control coupling occurs when modules share a composite data structure and use only part of it.

R: Content coupling occurs when one module modifies or relies on the internal working of another module.

(1) P and Q only

(2) P and R only

(3) Q and R only

(4) All of P, Q, and R

Answer 1

The correct selection is (2) P and R only. Common coupling shares global data and content coupling involves one module relying on another's internals. Control coupling is incorrectly described in Q.

Step-by-step explanation:

The correct answer is option (2) P and R only.

Common coupling occurs when two or more modules share access to the same global data. This type of coupling is generally discouraged, as it can lead to issues with data integrity and can make the system more complex and harder to maintain. Content coupling is considered the worst kind of coupling and happens when one module directly modifies or relies on the internal workings of another module, which breaks encapsulation and leads to a highly interdependent and fragile system structure.

As for the statement labeled Q, it incorrectly describes control coupling. Control coupling refers to a situation where one module controls the behavior of another by passing it information on what to do (e.g., a flag variable). Sharing a composite data structure and using only part of it is more indicative of a stamp coupling, not control coupling.