也是同一天的面試題。

給定一個數組"aa bb cee ee a"，使用int SawpWords(char *str)排序之後str的新順序為"a aa bb cee ee"；同時題中重點說明了防止記憶體洩漏問題。

也是沒有完全寫好，真的是手寫程式碼難呀，還是基礎不滿分。

回來之後認真研究了一下，把最終程式碼寫出來了。

void AddNewElementToList(list<char*> &lchr, char *ch)
{
	for (auto itor = lchr.begin(); itor != lchr.end(); ++itor)
	{
		if (strcmp(ch, *itor) < 0)
		{
			lchr.insert(itor, ch);
			return;
		}
	}
	lchr.push_back(ch);
	return;
}

int SwapWords(char *str)
{
	if (str == NULL)
		return -1;
	list<char*> lchr;
	int len = strlen(str) + 1;
	char *buff = new char[len];
	if (buff == NULL) return -1;
	memset(buff, 0, len);
	char *temp = str;
	int index = 0;
	while (*temp != '\0')
	{
		if (*temp == ' ')
		{
			if (strlen(buff) == 0)
			{
				++temp;
				index = 0;
				memset(buff, 0, len);
				continue;
			}
			char *newbuff = new char[strlen(buff) + 1];
			memset(newbuff, 0, strlen(buff) + 1);
			strcpy(newbuff, buff);
			AddNewElementToList(lchr, newbuff);
			memset(buff, 0, len);
			index = 0;
		}
		else
		{
			buff[index++] = *temp;
		}
		++temp;
	}
	if (index != 0)
	{
		char *newbuff = new char[strlen(buff) + 1];
		memset(newbuff, 0, strlen(buff) + 1);
		strcpy(newbuff, buff);
		AddNewElementToList(lchr, newbuff);
		memset(buff, 0, len);
		index = 0;
	}
	delete[] buff;
	buff = NULL;

	memset(str, 0, strlen(str));
	temp = str;
	for (auto itor = lchr.begin(); itor != lchr.end(); ++itor)
	{
		for (int i = 0; i < strlen(*itor); ++i)
		{
			temp[index++] = (*itor)[i];
		}
		auto tempitor = itor;
		tempitor++;
		if (tempitor != lchr.end())
		{
			temp[index++] = ' ';
		}
	}
	return 0;
}

void main()
{
	int len = 15;
	char *ch = new char[len];
	memset(ch, 0, len);
	strcpy(ch, " aa bb cee ee a ");
	int iret = SwapWords(ch);
	printf("iret=%d,(ch=%s)\n", iret, ch);
        return;
}