Rule: If ... else if constructs shall be terminated with an else clause

• Title
  If ... else if constructs shall be terminated with an else clause

• Description
  This rule applies whenever an if statement is followed by one or more else if statements; the final else if shall be followed by an else statement. In the case of a simple if statement then the else statement need not be included.

The requirement for a final else statement is defensive programming. The else statement should either take appropriate action or contain a suitable comment as to why no action is taken. This is consistent with the requirement to have a final default clause in a switch statement.

The following code snippet illustrates this rule:

  int x = 0;

  /* This "if" statement is fine, since it has no "else if" clause, no "else" is required */
  if (x == 0)
  {
    x = 42;
  }

  /* This "if" statement is also fine */
  if (x == 0)
  {
    x = 42;
  }
  else
  {
    x = -42;
  }

  /* This "if" statement is bad, because it has an "else if" but no "else" clause */
  if (x == 0) /* Non-Compliant */
  {
    x = 42;
  }
  else if (x == 1)
  {
    x = -42;
  }

• Violation message
  Add a final else to this If ... else if construct

• Default severity
  Major

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