WARNING

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Taking Inputs

In the last challenges, you wrote a function that took no inputs. But many functions do take inputs. When defining a function, expected inputs are called parameters. When calling a function, the inputs are called arguments. But in practice, you'll hear people use those terms interchangeably.

A parameter is just a variable. Its value is determined by the inputs passed to the function when it's called. To see an example, look at the starter code in the editor.

Order matters. When you run the code:

  • the first parameter will be assigned the first input
  • the second parameter will be assigned the second input
  • the third parameter will be assigned the third input

Try changing the inputs on line 8, where displayInputs is called. You should see the logged values change accordingly.

Tests

Let's write a function that takes a couple of inputs. Follow these directions. The tests will pass if you've correctly defined the function.

  • Type the keyword function
  • Give the function a name: subtract (it needs to match exactly)
  • Add parentheses ().
  • Inside the parentheses, add two parameters: firstNumber and secondNumber. Be sure to separate the two parameters with a comma.
  • Add a pair of curly braces {}.
  • Inside the curly braces, add a return statement: return firstNumber - secondNumber;

That's it! You just wrote a function that takes in two numbers, subtracts the second from the first, and returns the result.

You can try calling your function (and console logging the output) like so:

console.log(subtract(7, 3));

If you've done everything correctly, it should log the difference.