Binary string to number converter

bintoint.c

#include <stdio.h>

unsigned bintoint(char s[]) {
	int i, l;
	unsigned v = 0;
	for (l=-1; s[l+1] != '\0'; ++l);
	for (i=l; i>=0; --i)
		v += (s[i]-'0')<<(l-i);
	return v;
}

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