Fibonacci Number Generator (src)

"fib" (Fibonacci Number Generator) is a fast and cross-platform program that can be used to find a Fibonacci number. This small program works in a command-line and can be called in shell-scripts. Currently, the program cannot find Fibonacci numbers beyond the 410^th Fibonacci number. "fib" (Fibonacci Number Generator) is licensed under LGPLv3 and is made by Devyn Collier Johnson <[email protected]>.

NOTE: "fib" has been merged with "Linux-Utils" (https://dcjtech.info/topic/linux-utils-software-collection-for-linux/). Updates will be released with Linux-Utils rather than this page.

To compile the C-source-code, execute one of the below listed commands. Suggestions for other compiler commands are welcome.

• General (GNU GCC) - gcc -O3 -gtoggle -g0 -s -pipe -pedantic -std=c11 ./fib.c -o ./fib
• Optimized (GNU GCC) - gcc -O3 -gtoggle -g0 -s -pipe -funroll-loops -ffunction-sections -fdata-sections -std=c11 -Wl,-O3 ./fib.c -o ./fib && strip --remove-section=.note --remove-section=.comment --strip-debug --strip-unneeded ./fib

To use the program, in a terminal, type "/PATH/TO/fib 10" to get the tenth Fibonacci number.

Please feel free to email me suggestions, bug reports, concerns, etc. Also, please consider donating to DCJTech for further development.

[paypal-donation]

Download Version 2015.11.15

https://dcjtech.info/wp-content/uploads/2015/11/fib.c.tar.gz

Source Code

/*
Created by Devyn Collier Johnson
<[email protected]>
LGPLv3

GNU Lesser General Public License v3
Copyright (c) Devyn Collier Johnson, All rights reserved.

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 3.0 of the License, or (at your option) any later version.

This library 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
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library.
*/

// gcc -O3 -gtoggle -g0 -s -pipe -pedantic -std=c11 ./fib.c -o ./fib
// gcc -O3 -gtoggle -g0 -s -pipe -funroll-loops -ffunction-sections -fdata-sections -pedantic -Wall -Wextra -std=c11 -Wl,-O3 ./fib.c -o ./fib && strip --remove-section=.note --remove-section=.comment --strip-debug --strip-unneeded ./fib

// Fibonacci Number Generator
// Usage: ./fib 10  # Return the tenth Fibonacci number

#include <stdio.h>
#include <stdlib.h>


#if defined(__linux__)
#if !defined(_GNU_SOURCE)
#define _GNU_SOURCE
#endif
#include <unistd.h>
#elif !defined(_WIN32) && (defined(__unix__) || defined(__unix) || (defined(__APPLE__) && defined(__MACH__)))
#define _POSIX_C_SOURCE = 199309L
#include <unistd.h>
#if defined(__unix__) || (defined(__APPLE__) && defined(__MACH__))
#include <sys/param.h>
#if defined(BSD)
#define _XOPEN_SOURCE_EXTENDED
#endif
#endif
#endif


// static const char __author__[32] = "Devyn Collier Johnson";
// static const char __copyright__[8] = "LGPLv3";
// static const char __version__[16] = "2015.11.15";

unsigned int fib(const unsigned int num);


unsigned int fib(const unsigned int num) {
    // Fibonacci Number Generator
    unsigned int i;
    unsigned int fval[num+1];
    if (num > 410) {
        printf("ERROR! Number too large.\n");
        return 0;
    } else {
        if (num == 0) {
            return 0;
        } else if (num == 1 || num == 2) {
            return 1;
        } else {
            fval[0] = 0;
            fval[1] = 1;
            fval[2] = 1;
            fval[3] = 2;
            fval[4] = 3;
            for (i = 2; i <= num; i++) {
                fval[ i ] = fval[ i - 1 ] + fval[ i - 2 ];
            }
            return fval[num];
        }
    }
}


int main(int argc, char *argv[]) {
    printf("%u\n", fib((unsigned int) strtol(argv[1], (char **)NULL, 10)));
    return 0;
}