Hello fellow nairalanders just want to share a few O-O design “Code Smells“(code that can make software design harder to change) with you all. These are just a few of the common smells i have come across from my experience of performing O-O design and code refactoring so please feel free to add to the list below if u think i have omitted any. The list is as follows:

Duplicate code
Long methods
Big classes
Big switch statements
Long navigations (eg, a.b().c().d())
Too much checking for null objects
Data clumps (eg, a Contact class that has fields for address, phone, email etc) – similar to non-normalized tables in relational database design
Data classes (classes that have mainly fields/properties and little or no methods)
Un-encapsulated fields (public member variables)

Note that the above code smells have been listed from the c# programming language standpoint but i believe they are equally applicable to any O-O compliant language(java ,c++ etc).

"Eww, what is that smell. Your code stank!"