In App Lab, there’s a cool feature called “Functions” in the toolbox. This feature has two important blocks: one for defining a new function and another for calling a function.
Let’s say we want to make a function that updates the number of likes on the screen and plays a sound. We’ll name this function “updateScreen.” To start, drag out the “define a function” block. You might notice that some parts of your code, like the “on event” blocks, have the same commands repeated. We can make our code simpler by turning these repeated commands into a function.
Once you’ve created your function, you can remove the repeated code from the rest of your program. But wait! When you click “Run,” nothing happens. That’s because we forgot an important step: calling the function. To do this, drag out the “call a function” block from the toolbox and place it in your program. Then, type in the name of the function you defined.
Now that you’ve both defined and called your function, the code will run, and the likes will update on the screen. It works! Interestingly, even if you call the function before its definition in the code, it still works.
Defining a function means giving a name to a block of code, but it doesn’t actually run the code. You can place the function definition anywhere in your program, but putting them at the end helps keep your code neat and easy to read.
It’s important to give your function a clear and descriptive name. If you name it something vague like “do stuff,” it won’t be clear what the function does, making it hard to use in your code. A good name helps everyone understand what the function is supposed to do.
Using functions in your program not only makes your code easier to understand but also makes fixing problems simpler. If you fix an issue inside your function, it automatically fixes that problem everywhere the function is called. This makes your coding life much easier!
Imagine you are a game designer! Think of a simple task in a game, like updating a score or playing a sound. Use App Lab to define a new function for this task. Give your function a clear name that describes what it does. Share your function with a classmate and see if they can guess its purpose just by the name!
In pairs, explore a sample App Lab project provided by your teacher. Identify all the functions used in the project. Write down the names of these functions and discuss with your partner what each function might do. This will help you understand the importance of choosing descriptive names.
Work in small groups to create a simple app with multiple tasks. Each group member will define one function for a specific task, like changing the background color or displaying a message. Then, call each other’s functions in a sequence to complete the app. This activity will show you how functions can work together to build a complete program.
Your teacher will give you a piece of code with a bug in one of the functions. Work with a partner to find and fix the bug. Discuss how fixing the bug in the function affects the rest of the program. This will demonstrate how functions can simplify debugging.
Think of a task you do every day, like brushing your teeth or packing your school bag. Write a short description of this task and then create a function name that clearly describes it. Share your function name with the class and see if they can guess the task. This will help you practice creating descriptive function names.
Here’s a sanitized version of the provided YouTube transcript:
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In App Lab, the toolbox now has a tab called “Functions.” There are two blocks: one defines a new function, and the other calls a function.
Let’s create a function that updates the number of likes on the screen and plays a sound. We’ll call it “updateScreen.” First, drag out the “define a function” block. Notice that both “on event” blocks have the same last two commands. To simplify the program, we can turn these commands into a function.
Now we can remove the repeated code from the rest of the program. Click “Run.”
We defined a function, but nothing happened. The reason is that we forgot a crucial step: we need to call the function. Drag out the “call a function” block from the toolbox and place it in the program. Then, add the name of the function we just defined.
Now that we have both defined and called our function, the code will run, and the likes will change on the screen. It works! Notice that if I call the function before its definition, it still works.
Defining a function simply gives a name to a block of code, but it doesn’t actually run it. The definition can be placed anywhere in your program, which can make your code messy and hard to read. Therefore, we typically place our function definitions at the end of our programs to keep things organized.
It’s also important to give your function a meaningful and descriptive name. If you name it something vague like “do stuff,” it will be unclear what the function is supposed to do, making it difficult to use in your own code. A meaningful name makes it much easier to understand the function’s purpose.
Using functions in your program not only makes your code easier to understand, but it also simplifies fixing problems or errors. When you resolve an issue inside your function, it automatically fixes that problem wherever the function is called.
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This version removes unnecessary elements and maintains clarity while preserving the original content’s intent.
Functions – Functions are blocks of code that perform a specific task and can be used whenever needed in a program. – Example sentence: In our game, we use functions to make the character jump and collect coins.
Code – Code is a set of instructions written in a programming language that tells the computer what to do. – Example sentence: We wrote code to create a simple animation of a bouncing ball.
Program – A program is a complete set of code that runs on a computer to perform a specific task or solve a problem. – Example sentence: Our class project was to create a program that could calculate the total cost of items in a shopping cart.
Define – To define means to write the code that specifies what a function or variable will do in a program. – Example sentence: We need to define a function that will check if the player has won the game.
Call – To call means to use a function in your code so that the computer executes the instructions inside that function. – Example sentence: We call the draw function to display the game characters on the screen.
Update – To update means to change or modify something in the program to make it better or more current. – Example sentence: We need to update the program to include the new levels we designed.
Screen – The screen is the part of the computer where you can see the output of your code or program. – Example sentence: The game displays the score and time left on the screen.
Name – A name is a label given to a variable, function, or object in a program to identify it. – Example sentence: We gave the variable a name that describes what it stores, like “playerScore”.
Repeat – To repeat means to do the same set of instructions multiple times in a program, often using loops. – Example sentence: We use a loop to repeat the animation until the player presses the stop button.
Toolbox – A toolbox is a collection of tools or commands in a programming environment that helps you build your program. – Example sentence: The toolbox in our coding app has blocks for loops, conditions, and variables.
