GATE CSE 2009 | Question: 19

Question

The coupling between different modules of a software is categorized as follows:

1. Content coupling
2. Common coupling
3. Control coupling
4. Stamp coupling
5. Data coupling

Coupling between modules can be ranked in the order of strongest (least desirable) to weakest (most desirable) as follows:

• A. I-II-III-IV-V
• B. V-IV-III-II-I
• C. I-III-V-II-IV
• D. IV-II-V-III-I

Answer 1

Answer: A

Coupling between modules can be ranked in the order of strongest (least desirable) to weakest (most desirable) as follows: Content Coupling, Common Coupling, External Coupling, Control Coupling, Stamp Coupling, Data Coupling.

Answer 2

Answer A

Coupling between modules can be ranked in the order of strongest to weakest as follows:

Content Coupling $>$ Common Coupling $>$ External Coupling $>$ Control Coupling $>$ Stamp Coupling $>$ Data Coupling

• Content Coupling: Occurs when one module modifies or relies on the internal workings of another module
• Common Coupling: Occurs when two modules share the same global data
• External Coupling: Occurs when two modules share an externally imposed data format or communication protocol
• Control Coupling: One module controlling the flow of another, by passing it information
• Stamp Coupling: Occurs when modules share a composite data structure and use only parts of it
• Data coupling: Occurs when modules share data through parameters

Source: https://en.wikipedia.org/wiki/Coupling_(computer_programming)

Answer 3

Ranked highest to lowest:

1. Content coupling: if one directly references the contents of the other.

   When one module modifies local data values or instructions in another module. (can happen in assembly language)

   if one refers to local data in another module.

   if one branches into a local label of another.

2. Common coupling: access to global data.

   modules bound together by global data structures.

3. Control coupling: passing control flags (as parameters or globals) so that one module controls the sequence of processing steps in another module.
4. Stamp coupling: similar to common coupling except that global variables are shared selectively among routines that require the data. E.g., packages in Ada. More desirable than common coupling because fewer modules will have to be modified if a shared data structure is modified. Pass entire data structure but need only parts of it.
5. Data coupling: use of parameter lists to pass data items between routines.

so, ans A

ref: https://courses.cs.washington.edu/courses/cse403/96sp/coupling-cohesion.html