Prints out binary form of whatever is given.

base2.c

#include <stdio.h>

void printb(unsigned long v) {
	if (v>>1 > 0) printb(v>>1);
	putchar((v&1) + '0');
}

int main(int argc, char *argv[]) {
	if (argc > 1)
		printb(atol(argv[1]));
	printf("\n");
	return 0;
}