D: Functions


Every D programs begins with the main() function. This is the starting point for every D program. A function may return a value or be declared with void if nothing is returned. A function may also accept in any number of arguments (inputs).


Example: A User-Defined Function in D


	import std.stdio;
	void main()
	{
		int total;
		
		auto add(int x, int y) { // returns `int`
			return x + y;
		}
		total = add(2, 4);
		writeln("Total: ", total);
	}
	

If the return type is defined as auto, the D compiler infers the return type automatically.

Output:

  Total: 6


Example: A User-Defined Function in D


	import std.stdio;
	void main()
	{
		void printMenu() {
			writeln("0 - Exit");
			writeln("1 - Add Employee");
			writeln("2 - Search for an Employee");
			writeln("3 - Print Paycheck");
			writeln("4 - Query Benefits");
		}
		
		printMenu();
	}
	

If the return type is defined as auto, the D compiler infers the return type automatically.

Output:

  0 - Exit
  1 - Add Employee
  2 - Search for an Employee
  3 - Print Paycheck
  4 - Query Benefits