//                                     4 Button Door Lock
// ------------------------------------------------------
//                                              Your Name
//                                                 E-Mail

module debounce(CLK,SWITCH,OUT);
	input CLK;
	input SWITCH;
	output OUT;
	reg OUT;

	always @(posedge CLK)
	begin
		// ...
	end
endmodule

module main(CLK,SW2,SW3,SW4,SW5,LEDS);
	input CLK;		// Input clock
	input SW2,SW3,SW4,SW5;	// Switches, 1=on, 0=off

	output [9:0] LEDS;	// LED Bar Graph. 0=on, 1=off
	
	wire swa,swb,swc,swd;	// wires for debounced switches	
	// debounce switches
	debounce(CLK,SW2,swa);
	debounce(CLK,SW3,swb);
	debounce(CLK,SW4,swc);
	debounce(CLK,SW5,swd);

	reg [3:0]state;		// the current state of the state machine

	always @(posedge CLK)
	begin
		// ...
		case (state)
			4'd0 : ;
			4'd1 : ;
			// ...
			default : ;
		endcase
	end
endmodule