# Pascal - Bit Operators

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The Bitwise operators supported by Pascal are listed in the following table. Assume variable A holds 60 and variable B holds 13, then:

Operator | Description | Example |
---|---|---|

& | Binary AND Operator copies a bit to the result if it exists in both operands. | (A & B) will give 12, which is 0000 1100 |

| | Binary OR Operator copies a bit if it exists in either operand. | (A | B) will give 61, which is 0011 1101 |

! | Binary OR Operator copies a bit if it exists in either operand. Its same as | operator. | (A ! B) will give 61, which is 0011 1101 |

~ | Binary Ones Complement Operator is unary and has the effect of 'flipping' bits. | (~A ) will give -61, which is 1100 0011 in 2's complement form due to a signed binary number. |

<< | Binary Left Shift Operator. The left operands value is moved left by the number of bits specified by the right operand. | A << 2 will give 240, which is 1111 0000 |

>> | Binary Right Shift Operator. The left operands value is moved right by the number of bits specified by the right operand. | A >> 2 will give 15, which is 0000 1111 |

Please note that different implementations of Pascal differ in bitwise operators. Free Pascal, the compiler we used here, however, supports the following bitwise operators:

Operators | Operations |
---|---|

not | Bitwise NOT |

and | Bitwise AND |

or | Bitwise OR |

xor | Bitwise exclusive OR |

shl | Bitwise shift left |

shr | Bitwise shift right |

<< | Bitwise shift left |

>> | Bitwise shift right |

The following example illustrates the concept:

program beBitwise; var a, b, c: integer; begin a := 60; (* 60 = 0011 1100 *) b := 13; (* 13 = 0000 1101 *) c := 0; c := a and b; (* 12 = 0000 1100 *) writeln('Line 1 - Value of c is ', c ); c := a or b; (* 61 = 0011 1101 *) writeln('Line 2 - Value of c is ', c ); c := not a; (* -61 = 1100 0011 *) writeln('Line 3 - Value of c is ', c ); c := a << 2; (* 240 = 1111 0000 *) writeln('Line 4 - Value of c is ', c ); c := a >> 2; (* 15 = 0000 1111 *) writeln('Line 5 - Value of c is ', c ); end.

When the above code is compiled and executed, it produces the following result:

Line 1 - Value of c is 12 Line 2 - Value of c is 61 Line 3 - Value of c is -61 Line 4 - Value of c is 240 Line 5 - Value of c is 15