统计字符串中的单词数目

//统计字符串中的单词数目——统计字符串中单词的数目，更复杂的话从一个文本中读出字符串并生成单词数目统计结果。
/*
Test my2test,12test...?tesst
hehe,dsf..e3234...242haha
*/
//输出结果9
#include <iostream>
#include <fstream>
#include <string>
using namespace std;

int	CountWords(char* filename)
{
ifstream file(filename, ios::in);
if (!file.is_open())
return -1;
string word;
int count = 0;
int size = 0;
int index = 0;
int preindex = -1;

while (file >> word)
{
for (index = 0, preindex = -1, size = word.size(); index < size; ++index)
{
index = word.find_first_of("0123456789,.?", index);
if (index == string::npos)//查找结束
{
if (preindex == -1 || size > preindex + 1)
{
++count;
break;
}
}
else
{
if (preindex == -1 && index != 0 || index > preindex + 1)
{
++count;
}
preindex = index;
}
}
}
return count;
}

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

cout << CountWords("D:/test.txt") << endl;

system("pause");
return 0;
}