Else If chaining with unrelated expressions is bad style

Related expression chaining is GOOD

if (a == A)
    X;
else if (a == A2)
    Y;
else
    Z;

Unrelated expression chaining is BAD

if (a == A)
    X;
else if (b == B)
    Y;
else
    Z;

Nested Equivalent

if (a == A)
    X;
else
{
    if (b == B)
    {
        Y;
    }
    else
    {
        Z;
    }
}

Equivalence

if (A)
    X;
else if (B)
    Y;
else
    Z;

if (A)
    X;
else
{
    if (B)
        Y;
    else
        Z;
}

Truth table

Links

• http://c2.com/cgi/wiki?ElseConsideredSmelly
• http://c2.com/cgi/wiki?RefactorDefaultOrElse