#### 1.1.1 Function Header ¶

In our example, the first two lines of the function definition are the header. Its purpose is to state the function’s name and say how it is called:

    int
    fib (int n)

says that the function returns an integer (type `int`), its name is `fib`, and it takes one argument named `n` which is also an integer. (Data types will be explained later, in Primitive Data Types.)