89 lines
2.3 KiB
C
89 lines
2.3 KiB
C
/**
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* Copyright 2015 University of Applied Sciences Western Switzerland / Fribourg
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Module: MA-CSEL1 - Building Embedded Systems under Linux
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*
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* Abstract: Introduction to the Embedded Linux Development Environment
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*
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* Purpose: Fibonacci numbers: a simple demo program to exercice debugging
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* facilities on embedded Linux system.
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*
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* -->> tracing with printf
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*
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* Autĥor: Daniel Gachet
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* Date: 28.08.2015
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*/
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#include <stdio.h>
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#include <stdlib.h>
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/**
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* The Fibonacci numbers form a sequence of integers, mathematically defined by
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* F(0)=0; F(1)=1; F(n) = F(n - 1) + F(n - 2) for n > 1.
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*
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* This results in the following sequence of numbers: 0, 1, 1, 2, 3, 5, 8, 13,
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* 21, 34, 55, 89, 144, 233, 377, 610, 987, ...
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* so that each new number is the sum of the previous two, after seeding the
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* sequence with the starting pair 0, 1.
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*
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* @param n value for which the Fibonacci number should be computed
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* @return Fibonacci number
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*/
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long fibonacci_r(long n)
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{
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if (n <= 1)
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return n;
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return fibonacci_r(n - 1) + fibonacci_r(n - 2);
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}
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long fibonacci_i(long n)
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{
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long f0 = 0;
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long f1 = 1;
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while (n > 0)
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{
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f1 = f1 + f0;
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f0 = f1 - f0; // WAT !!!
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n--;
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}
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return f0;
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}
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/**
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* Main program computing the Fibonacci numbers for a given sequence starting
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* from 0 to a number specified at the command line.
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*/
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int main(int argc, char **argv)
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{
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long n = 0;
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long i = 0;
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if (argc == 2)
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{
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n = atol(argv[1]);
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}
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printf("%s, %d, %s, %s\n", __FILE__, __LINE__, __DATE__, __TIME__);
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printf("The first %ld Fibonacci numbers are:\n", n);
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for (i = 0; i < n; i++)
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{
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printf("%ld%s", fibonacci_i(i), i < n-1 ? ", " : "");
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}
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printf("\n");
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return 0;
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}
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