longatol(p)register char *p;{	long n;	register int f;	n = 0;	f = 0;	for(;;p++) {		switch(*p) {		case ' ':		case '\t':			continue;		case '-':			f++;		case '+':			p++;		}		break;	}	while(*p >= '0' && *p <= '9')		n = n*10 + *p++ - '0';	return(f? -n: n);}