Monica Wei

All programming languages have selection statements and repetition statements. What is the fundamental purpose of each type of statement? Give some examples of each including when you would use them. Programs can get complicated when you nest selections statements or repetition statements. Why do we nest them? Give examples. When wouldn’t you want to nest them?

All programming languages have selection statements and repetition statements, which are both fundamental for controlling the flow of a program.

Selection statements — such as if, if-else, and switch,  are used to make decisions and redirect the program flow based on certain conditions. In real-world programming, we often face situations where different conditions lead to different outcomes. For example, when grading students or evaluating employee performance, we may assign different grades or ratings based on their scores. Similarly, we may set different prices for different customer age groups or offer discounts during special time periods.

Repetition statements — including for, while, and do-while loops — are used when certain actions need to be repeated until a specific condition is met. For example, calculating the sum or average of a sequence of numbers, iterating over each element in an array or list to perform some operation, entering commands  in a game until the user chooses to quit, or selecting food items until the order is completed.

Nested statements are common — such as for-if, for-for, while-for — usually because the problem involves two or more dimensions. Examples include searching for specific value within a dataset, solving more complicated mathematical problems, dealing with both rows and columns, or performing multiple conditional checks.

We probably would not want to nest selection or repetition statements when the nesting makes the code too complicated or hard to read. Usually, one- or two-level nesting is acceptable, while over-nesting (more than three levels, for example) can lead to poor readability and make debugging or maintenance difficult. In such cases, it is better to simplify the logic, use helper methods, or apply logical operations.

References:

Liang, Y. D. (2022). Introduction to Java Programming and Data Structures, Comprehensive Version (12th ed.). Pearson.
Oracle. (n.d.). The Java™ Tutorials — Control Flow Statements. Oracle. https://docs.oracle.com/javase/tutorial/java/nutsandbolts/flow.html

Thank you for sharing!

I completely agree with you — the structure and function of repetition statements are truly impressive. Each type of repetition statement has its own usage rules and typical scenarios. When used thoughtfully and precisely, they help solve many practical programming problems. They’re also fundamental and commonly used across all programming languages!

I believe that once we’ve mastered the logic behind these statements in Java, it will be much easier to transfer that knowledge to other languages, such as Python, which is especially powerful for health data analytics.

Of course, it takes time and practice to become proficient in using these statements effectively — especially for beginners like me. But I feel a sense of accomplishment every time I make even a small step forward.

I’m glad you appreciate the beauty of their logic. I’m sure you’ve enjoyed the learning process and have mastered them well. After all, interest and passion are the best teachers.

Good luck!

Thank you for providing such a clear and structured explanation!
The introduction of selection statements and repetition statements, along with examples, gives a solid foundation for understanding how control flow works in programming.

Understanding the basic syntax, usage logic, and the differences between if-else, switch, while, for, and do-while statements is indeed critical — especially for beginners. These form the backbone of writing structured and logical programs.

For example:

Selection statements help the program make decisions. Choosing between if-else or switch depends on the situation — for example, switch is better suited for multiple fixed cases, while if-else is more flexible with condition checks.

Repetition statements (loops) are powerful for automation and repetitive tasks, but knowing when to use while, do-while, or for is key to writing efficient code.

Nested statements allow solving multi-layered logical problems, but overusing them can reduce code readability and increase complexity.

Forgetting to update loop variables or using incorrect conditions is a typical beginner’s mistake, often leading to infinite loops or unexpected behavior.

Overall, mastering these control structures not only helps avoid common errors but also lays a solid groundwork for writing more advanced, efficient, and maintainable code in the future.