/* * fib.c: Compute integral Fibonacci numbers using an iterative * algorithm, and using the C "unsigned long" data type. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * * Copyright (c) 2009 Paul E. McKenney, IBM Corporation. */ #include #include unsigned long fib(int x) { int i; unsigned long f0 = 0; unsigned long f1 = 1; unsigned long f2 = 1; for (i = 1; i < x; i++) { f2 = f1 + f0; f0 = f1; f1 = f2; } return f2; } unsigned long garbage; int main(int argc, char *argv[]) { int i; int x; if (argc != 2) { fprintf(stderr, "%s i\n", argv[0]); exit(-1); } x = atoi(argv[1]); printf("fib(%d) = %lu\n", x, fib(x)); for (i = 0; i < x; i++) garbage += fib(47); return 0; }