Algorithms are composed of three building blocks: sequencing, selection, and iteration. This unit focuses on selection, which is represented in a program by using conditional statements. Conditional statements give the program the ability to decide and respond appropriately and are a critical aspect of any nontrivial computer program. In addition to learning the syntax and proper use of conditional statements, students will build on the introduction of Boolean variables by writing Boolean expressions with relational and logical operators. The third building block of all algorithms is iteration, which you will cover in Unit 4. Selection and iteration work together to solve problems.
ESSENTIAL QUESTIONS
Control [CON]
How can you use different conditional statements to write a pick-your-own-path interactive story?
Why is selection a necessary part of programming languages?
BIG IDEAS
+ Finding Boolean values with expressions involving relational operators
+ Using conditional statements to execute different statements based on input values
+ Building on conditional statements to create multiple possible outcomes
+ Creating the same value using equivalent Boolean expressions
+ Referencing objects with aliases
UNIT TOPICS & ACTIVITIES
3.1: Boolean Expressions
3.2: if Statements and Control Flow
3.3: if-else Statements
3.4: else if Statements
3.5: Compound Boolean Expressions
3.6: Equivalent Boolean Expressions
3.7: Comparing Objects
SKILLS ADDRESSED
Code Logic
2.A: Apply the meaning of specific operators.
2.B: Determine the result or output based on statement execution order in a code segment without method calls (other than output).
2.C: Determine the result or output based on the statement execution order in a code segment containing method calls.
Code Implementation
3.C: Write program code to satisfy method specifications using expressions, conditional statements, and iterative statements.
Code Testing
4.A: Use test-cases to find errors or validate results.
4.C: Determine if two or more code segments yield equivalent results.