集合幂集的回溯实现-c

#include <ctype.h>
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#include <string.h>
#define OK 0
#define MAXLINE 100
int count=0;
void powerSet(int,int,char *,char *);
int main(int argc,char ** argv){
printf("the input set is :{a,b,c}\r\n");
printf("the powerset of the set is \r\n");
powerSet(0,3,"","abc");
printf("the number of the powerset is %d \r\n",count);
getchar();
return OK;
}
void powerSet(int index, int total, char * p, char *a){
char buf[MAXLINE];
assert(a);
assert(p);
if( index == 3){
printf("{%s}\r\n",p);
count++;
}else{
strcpy(buf,p);
powerSet(index+1,3,buf,a);
sprintf(buf,"%s %c ",p,a[index]);
powerSet(index+1,3,buf,a);
}
}