Delphi in a Nutshell

Name

And Keyword

Syntax

Boolean expression and Boolean expression
Integer expression and Integer expression

Description

The and operator performs a logical and if the operators are of Boolean type or a bitwise and if the operators are integers. Integer operands can be of any integer type, including Int64. A logical and is False if either operand is False and is True if both operands are True.

Tips and Tricks

• Unlike standard Pascal, if the left-hand operand is False, Delphi does not evaluate the right-hand operand because the result must be False. You can avoid this shortcut operation and return to standard Pascal with the $BoolEval or $B compiler directives.

• An integer and operates on each bit of its operands, setting the result bit to zero if either operand has a zero bit, and sets a bit to one if both operands have 1 bits. If one operand is smaller than the other, Delphi extends the smaller operand with zero in the leftmost bits. The result is the size of the largest operand.

Examples

var
  I, J: Integer;
  S: string;
begin
  I := $F0;
  J := $8F;
  WriteLn(I and J); // Writes 128 (which is $80)

  // The short-circuit behavior of AND in the next example prevents
  // Delphi from referring to the nonexistent string element, S[1].
  S := '';
  if (Length(S) > 0) and (S[1] = 'X') then
    Delete(S, 1, 1);

See Also

Boolean Type, ByteBool Type, LongBool Type, Not Keyword, Or Keyword, Shl Keyword, Shr Keyword, WordBool Type,

Xor Keyword, $B Compiler Directive, $BoolEval Compiler Directive