字符串全排列

/*    28:> 字符串全排列    递归，子问题求解    将首字母和后面每一个字母交换，对处理后的序列做相同处理（str+1）*/void  perm(char* pStr, char* pBegin);void perm(char* pStr){    if (pStr == NULL)        return;    perm(pStr,pStr);}void  perm(char* pStr,char* pBegin){    if (*pBegin == '\0')        cout << pStr << endl;    else    {        for (char* pCh = pBegin; *pCh != '\0'; ++pCh)        {            std::swap(*pCh,*pBegin);            perm(pStr,pBegin+1);            std::swap(*pCh, *pBegin);        }    }}//void test()//{//  char ar[4] = {'a','b','c'};//  perm(ar);//}