#### 22.1.2 Forward Function Declarations ¶

The order of the function definitions in the source code makes no difference, except that each function needs to be defined or declared before code uses it.

The definition of a function also declares its name for the rest of the containing scope. But what if you want to call the function before its definition? To permit that, write a compatible declaration of the same function, before the first call. A declaration that prefigures a subsequent definition in this way is called a forward declaration. The function declaration can be at top level or within a block, and it applies until the end of the containing scope.

See Function Declarations, for more information about these declarations.