28 lines
1.1 KiB
C
28 lines
1.1 KiB
C
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#include <stdio.h>
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#include <stdlib.h>
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unsigned long long fib(unsigned long long n) {
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unsigned long long r; // Declare a local variable r
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if (n == 0) { // If n is zero, return 0.
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r = 0;
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} else if (n == 1) { // If n is one, return 1.
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r = 1;
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} else { // Else, calculate the number
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r = fib(n-1) + fib(n-2); // to return by utilising
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} // recursion.
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return r;
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}
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int main(int argc, char *argv[]) {
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unsigned long long n, r; // Define local variables
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n = atoll(argv[1]); // Convert the first argument
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// to a long long value and
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// load it into n.
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r = fib(n); // Set the variable r to the
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// n'th Fibonacci number.
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// Print the number found.
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printf("fib(%lld) = %lld\n", n, r);
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return 0; // Return 0 to indicate a
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// successful execution.
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}
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