/* ------------------------------------------------------ *//* PROGRAM Subset Listing :                               *//*    This program lists all subsets, including empty set,*//* of a given set with elements {1,2,...,n} by using a    *//* direct generation method.                              *//*                                                        *//* Copyright Ching-Kuang Shene               July/04/1989 *//* ------------------------------------------------------ */ #include  <stdio.h>#include  <stdlib.h> #define   MAXSIZE   20#define   LOOP       1 void main(void){     char digit[MAXSIZE];     int  i, j;     int  n;     char line[100];      printf("\nDirect Generation of All Subsets of a Set");     printf("\n=========================================");     printf("\n\nNumber of Elements in the Given Set --> ");     gets(line);     n = atoi(line);      /* ---You'd better check to see if n is too large--- */      for (i = 0; i < n; i++)  /* clear all digits to 0    */          digit[i] = '0';      printf("\n{}");          /* outpout empty set {}     */     while (LOOP) {          for (i = 0; i < n && digit[i] == '1'; digit[i] = '0', i++)               ;              /* find first 0 position    */          if (i == n)         /* if none, all pos. are 1  */               break;         /* thus all elem. are in set*/          else               digit[i] = '1';/* now add one to this pos  */           for (i = 0; i < n && digit[i] == '0'; i++)               ;              /* find first 1 position    */          printf("\n{%d", i+1);  /* show its numner and   */          for (j = i + 1; j < n; j++) /* others           */               if (digit[j] == '1')                    printf(",%d", j + 1);          printf("}");     }}

评论