0x00 Lesson

Functions become more powerful when they can be customized each time you run them. Swift lets you send values to a function that can then be used inside the function to change the way it behaves. We’ve used this already - we’ve been sending strings and integers to the ​​print()​​ function, like this:

print("Hello, world!")

Values sent into functions this way are called ​​parameters​​.

To make your own functions accept parameters, give each parameter a name, then a colon, then tell Swift the type of data it must be. All this goes inside the parentheses after your function name.

For example, we can write a function to print the square of any number:

func square(number: Int) {
  print(number * number)
}

That tells Swift we expect to receive an ​​Int​​​, and it should be called ​​number​​. This name is used both inside the function when you want to refer to the parameter, but also when you run the function. like this:

square(number: 8)

0x01 我的小作品

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