Having two ``++cases++`` in the same ``++switch++`` statement or branches in the same ``++if++`` structure with the same implementation is at best duplicate code, and at worst a coding error. If the same logic is truly needed for both instances, then in an ``++if++`` structure they should be combined, or for a ``++switch++``, one should fall through to the other.

== Noncompliant Code Example

----
switch (i)
{
  case 1:
    DoFirst();
    DoSomething();
    break;
  case 2:
    DoSomethingDifferent();
    break;
  case 3:  // Noncompliant; duplicates case 1's implementation
    DoFirst();
    DoSomething();
    break;
  default:
    DoTheRest();
}

if (a >= 0 && a < 10)
{
  DoFirst();
  DoTheThing();
}
else if (a >= 10 && a < 20)
{
  DoTheOtherThing();
}
else if (a >= 20 && a < 50)   // Noncompliant; duplicates first condition
{
  DoFirst();
  DoTheThing(); 
}
----

== Exceptions

Blocks in an ``++if++`` chain that contain a single line of code are ignored, as are blocks in a ``++switch++`` statement that contain a single line of code with or without a following ``++break++``.


----
if (a >= 0 && a < 10)
{
  DoTheThing();
}
else if (a >= 10 && a < 20)
{
  DoTheOtherThing();
}
else if (a >= 20 && a < 50)    //no issue, usually this is done on purpose to increase the readability
{
  DoTheThing(); 
}
----

But this exception does not apply to ``++if++`` chains without ``++else++``-s, or to ``++switch++``-es without default clauses when all branches have the same single line of code. In case of ``++if++`` chains with ``++else++``-s, or of ``++switch++``-es with default clauses, rule S3923 raises a bug. 

----
if(a == 1) 
{
  doSomething();  //Noncompliant, this might have been done on purpose but probably not
} 
else if (a == 2) 
{
  doSomething();
}
----

ifdef::rspecator-view[]
== Comments And Links
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include::../comments-and-links.adoc[]
endif::rspecator-view[]