Why Use cases? - Purpose & Use Cases

The Big Idea

What if your program could handle every situation without confusing code?

The Scenario

Imagine you have to write a program that behaves differently depending on the situation, like a vending machine that gives snacks, drinks, or refunds money based on user input.

The Problem

Without clear use cases, you might write many if-else statements scattered everywhere. This makes your code messy, hard to read, and easy to break when you add new features.

The Solution

Use cases help you plan and organize your program's behavior clearly. They show exactly what should happen in each situation, making your code simpler and easier to manage.

Before vs After

✗ Before

if (input == 1) { giveSnack(); } else if (input == 2) { giveDrink(); } else { refund(); }

✓ After

switch (input) { case 1: giveSnack(); break; case 2: giveDrink(); break; default: refund(); break; }

What It Enables

Use cases let you build programs that handle many different situations smoothly and predictably.

Real Life Example

Think of an elevator system: use cases define what happens when someone presses a floor button, when the door opens, or when the elevator is full.

Key Takeaways

Use cases clarify what your program should do in each situation.

They prevent messy and error-prone code by organizing behavior clearly.

Use cases make adding new features easier and safer.