Having an understanding of how our iPhone reads our code as a line by line recipe can help us understand the need for the concept of a function.

Let's imagine, for a moment, that we do not have any concept of functions when writing our code. Then, if we want to make a simple app that simulates the making of a pizza, we can write the following code:

print("Flattening the dough to form a round pizza ")
print("Adding some tomato sauce ")
print("Adding some mozzarella cheese ")
print("Adding some spicy pepperoni ")
print("Preparing the pizza in the oven ")
print("Done! Delicious pizza ready to be eaten ")

When we run this application, it will simply output the simulation of making a pizza to the console:

How will we write our code if we want our program to make multiple pizzas? The first thing that comes to mind...