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### if

#### Synopsis

    if Boolean_expression then
      statement

or with an alternative statement:

    if Boolean_expression then
      statement1
    else
      statement2

#### Description

The `if ... then` statement executes statement1 depending on `Boolean expression` being true. If `else` is specified, it continues executing statement2 instead.

#### Conforming to

`if` is defined in ISO 7185 Pascal and supported by all Pascal variants.

#### Example

    program IfDemo;
    var
      Foo, Bar: Boolean;
    begin
      Foo := True;
      Bar := False;
      if ((1 = 1) or (2 = 3)) and (Foo = not Bar) then
        begin
          { This is executed if either Foo is true but not Bar or vice versa }
          WriteLn ('Either Foo or Bar is true.');
          if Bar then
            WriteLn ('You will see this text if Bar is true.')
        end
      else { This whole `else' branch is not executed }
        if 1 = 1 then
          if True = False then
            WriteLn ('This text is never written on screen.')
          else  { Note: This ``else'' belongs to ``if True = False'' }
            WriteLn ('This text is never written on screen as well.')
        else  { Note: This ``else'' belongs to ``if 1 = 1'' }
          WriteLn ('Nor is this.')
    end.

#### See also

Keywords, if Statement, else, then