DCPUC doesn't actually support varidic arguments. The implementation of printf here demonstrates how to implement them.

gistfile1.txt

#ifndef DCPUC_DEFAULT_ENVIRONMENT
#define DCPUC_DEFAULT_ENVIRONMENT

#include lem.dc
#include console.dc

static lem;
lem = detect_lem();  						//Find a lem screen
static lem_vram;
lem_vram = __endofprogram;					//Stick video ram at the end of the program.
initialize_lem(lem, lem_vram);				//Initialize the lem display
static console[sizeof(console)];			//Allocate space for the console
console_make(console, lem_vram);			//Create the console

static printf;
printf = &__printf;

#define VARARG(which, into) asm (A = which; B = &into; C = 0) { SET C, J; ADD C, A; SET [B], [C] }

function __printf(string)
{
	local index = 0;
	local strlen = veclen(string);
	local parameter_index = 3; //The first parameter is at J + 2.
	local number_buffer[32];
	while (index < strlen)
	{
		if (string[index + 1] == '%') //Found a key code.
		{
			local parameter = 0;
			VARARG(parameter_index, parameter);
			parameter_index += 1;
			itoa(parameter, number_buffer);
			console_stringout(console, number_buffer);
		}
		else
		{
			console_charout(console, string[index + 1]);
		}
		index += 1;
	}
}

function __itoa(number, buffer)
{
	if (number > 9) __itoa(number / 10, buffer);
	buffer[0] += 1;
	buffer[buffer[0]] = '0' + (number % 10);
}

function itoa(number, buffer)
{
	buffer[0] = 0;
	__itoa(number, buffer);
}

#endif