Transcript

Welcome again to iview Tech Hub Day 16 and thank you for joining this lesson. In this video you will learn functions, Part 2, arguments, parameters, and return values. In the previous lesson you learned how to define and call functions. But real programs become powerful when functions can accept information and give results back. That is what we are learning today. Think of a function like a small machine. You give it some input, it processes the input and it gives you an output. That input is called. An argument inside the function. That input is stored in something called a parameter. Let's understand this clearly. First, a quick recall. A simple function with no parameters looks like this. We define it, we call it and it prints our message. Now let's add a parameter. When we define a function, we can include a variable inside the parentheses. That variable is called a parameter. It acts as a placeholder. That name is the parameter when we call the function and provide a real value like ada that value. Called the argument. So remember this. Parameters are in the function definition. Arguments are the actual values you pass when calling the function. Functions can accept more than one parameter. For example, we might want a function that adds 2 numbers. We define two parameters inside the parentheses. When calling the function, we provide 2 arguments. The function then uses those values to perform its task. This is how programs become dynamic. Instead of writing separate code for every calculation, we write 1 reusable function and supply different arguments each time. Now let's talk about something very important, return values. So far we have been printing results inside functions, but printing is not the same as returning. When a function prints something, it simply displays it on the screen. But when a function. Returns something. It sends that value back to where the function was called. That returned value can then be stored in a variable, used in calculations, or passed into another function. Look what happens if we don't return. The function prints 8, but the variable result gets None. This means the value didn't actually come back to us. For example, if we create a function that adds 2 numbers, instead of printing, we use the return keyword. When we call the function, we can store the result in a variable like. Result. Now we can print it, multiply it, or use it anywhere else. Let's make this practical. Imagine we create a function that calculates the area of a rectangle. It calculates the area and returns the result. Notice what happened here. The function received input, processed it, and returned output. That is exactly how real software systems work. Functions with parameters and return values allow us to build calculators, grading systems, login systems. And data processors. Now here is something important for beginners to understand. If you forget to use return, your function will automatically return something called None. That means no useful value was sent back. So whenever you need a result from a function, make sure you use return. Let's quickly summarize. Parameters are variables listed when defining a function, arguments are the real values passed when calling the function, and return values are the results sent back from the. Function to be used elsewhere in the program. This concept may seem small, but it changes everything. With arguments and return values, your functions become flexible, reusable and powerful. Before we end try this practice, create a function that multiplies 2 numbers and returns the result. Then call it with different values and store the result in a variable. Predict the output before running the program. Functions are the building blocks of real applications mastering arguments. Parameters and return values means you are thinking like a programmer. Keep practising, experiment with different inputs and I will see you in the next lesson.