给出一个函数来输出一个字符串的所有排列

#include "stdio.h"
#include "stdlib.h"
#include "string.h"

void permutation(char * p_str, char * p_begin)
{
if(!p_str || !p_begin)
{
return;
}

if('\0' == *p_begin)
{
printf("%s\n", p_str);
}

else
{
char * p_ch;

for(p_ch = p_begin; *p_ch != '\0'; ++p_ch)
{
char temp;

temp = *p_ch;
*p_ch = *p_begin;
*p_begin = temp;

permutation(p_str, p_begin + 1);
// a b c d
//

//(*p_ch != *p_begin)

temp = *p_ch;
*p_ch = *p_begin;
*p_begin = temp;

}
}
}

int main(int argc, char * argv[])
{

char strr[6]="123";
// 1 3 3
//
//char strd[4];
permutation(strr, strr);
return 0;
}