Study Notes on Boolean Variables and Operators

Boolean Variables and Operators

• Evaluate logical conditions in programming using boolean variables.
• Boolean variables can hold two values: TRUE or FALSE.
• Boolean operations express complicated conditions.

Boolean Data Type in C++

• bool type represents Boolean values.
• Values: true and false, not strings or integers.
• Example of defining a Boolean variable: bool isLegalAge = false;

Boolean Operations

• AND (&&): Evaluates to true if both operands are true.   - Example: if (shark_free && sunny)
• OR (||): Evaluates to true if at least one operand is true.   - Example: if (sharks || rainy)
• NOT (!): Evaluates to true if the operand is false.   - Example: if (!shark_free)

Complex Conditions

• Use parentheses to define order of evaluation in complex conditions.
• Common errors include misusing && and ||.

DeMorgan’s Law

• Defines how to negate expressions:   - !(A && B) = !A || !B   - !(A || B) = !A && !B

Input Validation

• Validate user input to prevent errors in programs (e.g., invalid floor number).
• Check for input failures with cin.fail().

Implementing Decisions with if Statements

• Use if statements to execute different actions based on conditions.
• Use relational operators for comparisons: <, <=, >, >=, ==, !=.
• Nested if statements allow for complex decision-making.

Summary

• Store conditions with bool, combine conditions with &&, ||, and invert with !.
• Validate and test user input to ensure correctness.