1 / 11

Logic and Boolean Expressions

Logic and Boolean Expressions. CPSC 110. Decision-Making With Multiple Expressions. Format: if (Boolean-expression) logical-operator (Boolean-expression) then body ; Example: if (x > 0) AND (y > 0) then writeln ('X is positive, Y is positive') ;.

kasi
Télécharger la présentation

Logic and Boolean Expressions

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Logic and Boolean Expressions CPSC 110 J. Michael Moore

  2. Decision-Making With Multiple Expressions • Format: if (Boolean-expression) logical-operator (Boolean-expression) then body; • Example: if (x > 0) AND (y > 0) then writeln ('X is positive, Y is positive'); J. Michael Moore

  3. Decision-Making With Multiple Expressions (2) • Built-in logical operators in Pascal • _____ • _____ • _____ • _____ • (NAND and NOR can be constructed by combining _____ with _____ & _____ with _____) J. Michael Moore

  4. Compound Boolean Expressions With “OR” Operator • Format: if (Boolean-expression) OR (Boolean-expression) then body; • Example: if (gpa > 3.7) OR (yearsJobExperience > 5) then writeln(‘You are hired’); J. Michael Moore

  5. Compound Boolean Expressions With “AND” Operator • Format: if (Boolean-expression) AND (Boolean-expression) then body; • Example: if (yearsOnJob <= 2) AND (isGoofOff = True) then writeln(‘You are fired’); J. Michael Moore

  6. Compound Boolean Expressions With “XOR” Operator • Format: if (Boolean expression) XOR (Boolean expression) then body; • Example: if (takesFirstJob = true) XOR (takesSecondJob = true) then isEmployed := true; OR if (takesFirstJob) XOR (takesSecondJob) then isEmployed := true; J. Michael Moore

  7. Compound Boolean Expressions With “NOT” Operator • Format: if NOT (Boolean expression) then body; • Examples: if NOT (x AND y) then writeln(‘NAND’); if NOT (x OR y) then writeln(‘NOR’); J. Michael Moore

  8. Order Of The Operations Order/Priority Operator • ___ • ___ ___ ___ ___ ___ • ___ ___ ___ • ___ ___ ___ ___ ___ ___ J. Michael Moore

  9. AND has ___________ so the ‘0’ and ‘y’ become operands for this operation Why Bracket Boolean Expressions • Compound Boolean expressions • e.g., if x > 0 AND y > 0 then J. Michael Moore

  10. Range Checking • What about doing (x < y < z) to check if y is in the proper range? • Use _______________________ J. Michael Moore

  11. Quick Summary: Using Multiple Expressions • Use multiple expressions when multiple Boolean expressions must be asked and the result of each expression may have an effect on the other expressions: • AND: • All Boolean expressions must evaluate to true before the entire expression is true. • If any expression is false then whole expression evaluates to false • OR: • If any Boolean expression evaluates to true then the entire expression evaluates to true. • All Boolean expressions must evaluate to false before the entire expression is false. J. Michael Moore

More Related