Boolean Expressions in Algorithms and Programming
students, imagine you are writing a program for a school club app that decides whether a student can enter a locked event. The app might need to check things like whether the student has a ticket, whether they are on the guest list, and whether the doors are open. To make that decision, the program uses Boolean expressions ✅. These are a key part of AP Computer Science Principles because programs often need to make choices based on true-or-false conditions.
Lesson objectives:
- Explain what Boolean expressions are and how they work.
- Use Boolean logic to reason about program decisions.
- Connect Boolean expressions to algorithms, conditionals, and program flow.
- Interpret examples of Boolean expressions in AP CSP style problems.
- Summarize why Boolean expressions matter in real programs.
What Is a Boolean Expression?
A Boolean expression is any expression that evaluates to one of two values: $\text{true}$ or $\text{false}$. In computer science, these values are often used to answer yes-or-no questions. For example, the statement $\text{age} \ge 13$ is Boolean if $\text{age}$ is a number. If $\text{age} = 15$, then the expression is $\text{true}$. If $\text{age} = 10$, it is $\text{false}$.
Boolean expressions are named after George Boole, whose ideas helped create Boolean logic. In programming, Boolean expressions are important because they help a computer decide what to do next. A program can compare values, check conditions, and combine multiple tests into one decision.
Common comparison operators include:
- $==$ means equal to
- $\ne$ means not equal to
- $>$ means greater than
- $<$ means less than
- $\ge$ means greater than or equal to
- $\le$ means less than or equal to
For example:
- $\text{score} \ge 80$
- $\text{username} == $\text{
Study Notes
- Review the key concepts covered in this lesson.