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#ifndef lint |
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static const char RCSid[] = "$Id: cnt.c,v 1.2 2003/06/08 12:03:09 schorsch Exp $"; |
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#endif |
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/* |
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* cnt.c - simple counting program. |
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* |
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* 2/1/88 |
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* |
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* Added -s (shuffle) option April 2022 |
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*/ |
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|
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#include <stdio.h> |
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#include <time.h> |
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#include "random.h" |
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|
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#define MAXDIM 50 |
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|
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char buf[256]; |
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|
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|
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/* Encode integer in string and return pointer to end */ |
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static char * |
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tack( |
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char *b, |
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int i |
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) |
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{ |
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char *cp; |
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char *res; |
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|
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*b++ = '\t'; |
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cp = b; |
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if (i == 0) |
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*cp++ = '0'; |
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else |
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do { |
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*cp++ = i%10 + '0'; |
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i /= 10; |
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} while (i); |
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res = cp--; |
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#define c i |
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while (cp > b) { /* reverse string */ |
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c = *cp; |
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*cp-- = *b; |
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*b++ = c; |
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} |
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#undef c |
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return(res); |
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} |
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|
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|
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/* Loop over dimensions, spitting out buffer after each increment */ |
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static void |
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loop( |
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int *n, |
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char *b |
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) |
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{ |
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int i; |
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|
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if (n[0] == 0) { |
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*b = '\0'; |
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puts(buf); |
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return; |
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} |
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for (i = 0; i < n[0]; i++) |
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loop(n+1, tack(b, i)); |
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} |
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|
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|
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/* Shuffle all possible output strings and spit out randomly */ |
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static void |
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shuffle( |
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int *n |
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) |
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{ |
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int sub[MAXDIM]; |
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int ndim; |
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int alen; |
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int *myshuf; |
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int i, j; |
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|
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alen = 1; /* allocate shuffle index array */ |
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for (j = 0; n[j]; j++) |
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if ((alen *= n[j]) < 0) |
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exit(1); |
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|
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myshuf = (int *)malloc(alen*sizeof(int)); |
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if (myshuf == NULL) { |
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fputs("Insufficient memory for shuffle\n", stderr); |
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exit(1); |
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} |
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for (i = alen; i--; ) /* initialize in any order */ |
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myshuf[i] = i; |
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/* get unique starting point */ |
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srandom((long)time(0)); |
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/* perform Fisher-Yates shuffle */ |
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for (i = 0; i < alen-1; i++) { |
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int ix = random()%(alen-i) + i; |
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int ndx = myshuf[i]; |
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myshuf[i] = myshuf[ix]; |
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myshuf[ix] = ndx; |
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} |
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/* put randomly indexed output */ |
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for (i = alen; i--; ) { |
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int aval = myshuf[i]; |
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for (j = 0; n[j+1]; j++) { |
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printf("\t%d", aval % n[j]); |
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aval /= n[j]; |
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} |
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printf("\t%d\n", aval); |
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} |
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free(myshuf); |
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} |
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|
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|
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int |
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main( |
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int argc, |
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char *argv[] |
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) |
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{ |
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char *prog = argv[0]; |
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int doshuffle = 0; |
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int n[MAXDIM]; |
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int a; |
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|
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argv++; argc--; |
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if (argc <= 0) |
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goto userr; |
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if (argv[0][0] == '-' && argv[0][1] == 's') { |
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doshuffle = 1; |
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argv++; argc--; |
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} |
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for (a = 0; a < argc; a++) |
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if ((n[a] = atoi(argv[a])) <= 1) |
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goto userr; |
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n[a] = 0; |
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if (!a) |
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goto userr; |
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|
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if (doshuffle) |
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shuffle(n); |
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else |
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loop(n, buf); |
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|
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return(0); |
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userr: |
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fputs("Usage: ", stderr); |
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fputs(prog, stderr); |
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fputs(" [-s] N0 [N1 ..]\n", stderr); |
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return(1); |
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} |
