A chain of if/else if statements is evaluated from top to bottom. At most, only one branch will be executed: the first
one with a condition that evaluates to true.
Therefore, duplicating a condition automatically leads to dead code. Usually, this is due to a copy/paste error. At best, it’s simply dead code and
at worst, it’s a bug that is likely to induce further bugs as the code is maintained, and obviously it could lead to unexpected behavior.
Noncompliant code example
if (param == 1)
openWindow();
else if (param == 2)
closeWindow();
else if (param == 1) // Noncompliant
moveWindowToTheBackground();
Compliant solution
if (param == 1)
openWindow();
else if (param == 2)
closeWindow();
else if (param == 3)
moveWindowToTheBackground();
