68 lines
1.5 KiB
C++
68 lines
1.5 KiB
C++
/*****************************************************************
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*
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* Ackermann
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*
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* This program implements a famous mathematical function that
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* is often used to examine recursion. It is deceptively
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* simple, but can take enormous amounts of time and stack
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* space for relatively small arguments. For that reason,
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* rangechecking has been enabled to ensure the integrity of the
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* stack.
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*
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* By Mike Westerfield
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*
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* Copyright 1987-1989
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* Byte Works, Inc.
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*
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*****************************************************************/
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#pragma keep "Ackermann"
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#pragma debug 0x0001
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#pragma lint -1
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#include <stdio.h>
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/* Constants */
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#define maxm 2 /* max value of 1st argument */
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#define maxn 3 /* max value of 2nd argument */
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/* Global variables */
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int a, m, n, depth, maxdepth;
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/****************************************************************
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*
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* Ackermann - Demonstrates recursion in ORCA/C
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*
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****************************************************************/
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int Ackermann (int m, int n)
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{
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int result;
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depth++;
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if (depth > maxdepth)
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maxdepth = depth;
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if (m == 0)
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return (n + 1);
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if (n == 0)
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return (Ackermann (m-1, 1));
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result = Ackermann (m-1, Ackermann (m, n-1));
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depth--;
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return result;
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}
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int main (void)
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{
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for (m = 0; m <= maxm; m++)
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for (n = 0; n <= maxn; n++) {
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depth = 0;
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maxdepth = 0;
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a = Ackermann (m, n);
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printf ("Ackermann(%d, %d) = %-4d ", m, n, a);
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printf ("Max recursion depth was %d\n", maxdepth);
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}
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}
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