U3L8 Creating Functions with Parameters CS Principles U3L8 Creating Functions with Parameters

U3L8 Creating Functions with Parameters Objectives SWBAT: Write functions with parameters to generalize a solution instead of duplicating code. Identify appropriate situations for creating a function with parameters. Use random numbers as inputs to function calls for the purpose of testing. Add parameters to a function in an existing piece of code to generalize its behavior.

U3L8 Content: Creating Functions with Parameters You often want to write a function that takes some input and performs some action based on that input. For example, the turtle function moveForward is much more useful when you can specify how much to move forward (e.g., moveForward(100)), rather than just a fixed amount every time. It’s very common to encounter situations where as a programmer you need a duplicate of some code, but you just want to change some numbers. That’s a good time to write a function with a parameter; the parameter just acts as a placeholder for some value that you plug in at the time you call the function. It’s considered good practice to give descriptive names to your functions; the same is true for the names of the parameters themselves. For example: drawSquare(sideLength) is better than drawSquare(stuff).

U3L8 Vocabulary Parameter - An extra piece of information that you pass to the function to customize it for a specific need. randomNumber(min, max) – Function that returns a random number in the closed range from min to max. Define a function - When you define a function you give a name to a set of actions you want the computer to perform.  Call a function - When you call a function you are telling the computer to run (or execute) that set of actions. When you call a function with parameters you must match the order of parameters in the function definition. Define a function with parameters: Gives a name to a set of parameter driven actions you want the computer to perform, and optionally return a value. Some functions take parameter values as input to be able to abstract multiple different actions.

U3L8 Stage 1 Clink on the links in U3L8 Stage 1 in the New Blocks section and read the explanations and examples before beginning work on code studio. Random Number min/max: https://docs.code.org/applab/randomNumber_min_max/ Call a function with parameters: https://docs.code.org/applab/callMyFunction_n/ Define a function with parameters: https://docs.code.org/applab/functionParams_n/

U3L8 Video (stage 2) and Code Studio In the previous lesson, we learned to use a lot of new turtle commands. Some of these commands accept a parameter, or even many parameters, which allow us to pass values to the function. This allowed us to make much more interesting images by specifying precisely how far the turtle should move or turn, and introduced the ability to choose specific pen sizes and colors. Parameters are a powerful programming construct. Suppose we have a whole group of similar problems, like turning the turtle some amount. Without a parameter we would need 360 different functions, one for each number of degrees we wanted to turn! Parameters allow us to use a single function as a general solution to a whole group of problems. This is clearly a useful construct to use in our programs, and in today’s lesson we’re going to learn how to create functions with parameters for ourselves. Watch the video in U3L8 Code Studio Stage 2, and complete the rest of code studio stages 3-20.

U3L8 Prompt Prompt: “Develop a rule for deciding when to create a function with a parameter rather than a normal function. Below your rule write a couple sentences justifying your rule.“