Last time, we learned how to build practical Go functions that take parameters and return values. But have you noticed something interesting about variables inside functions versus variables outside them?

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Where exactly do variables "live" in our Go programs?

Variables created inside a function have local scope - they only exist within that function. These local variables are born when the function starts and disappear when it ends.

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What do you think happens to the result variable after the function finishes?

Local variables can't be accessed from outside their function. This code would cause an error because result doesn't exist outside the function:

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Why do you think this protection exists?

Variables created outside functions have global scope – they can be accessed from anywhere in the program, including inside functions:

Notice that to make a global variable, we use var outside any function. The := shortcut only works inside functions, not at the top level of your code. That's why is used here.