c++指定分隔符以从文本文件中读取单词

Question

我有以下代码打印文本文件中的每个唯一单词及其计数(包含 >= 30k 单词)，但是它用空格分隔单词，我得到的结果如下:

如何修改代码以指定预期的分隔符？

template <class KTy, class Ty>
void PrintMap(map<KTy, Ty> map)
{
    typedef std::map<KTy, Ty>::iterator iterator;
    for (iterator p = map.begin(); p != map.end(); p++)
        cout << p->first << ": " << p->second << endl;
}

void UniqueWords(string fileName) {
    // Will store the word and count.
    map<string, unsigned int> wordsCount;

    // Begin reading from file:
    ifstream fileStream(fileName);

    // Check if we've opened the file (as we should have).
    if (fileStream.is_open())
        while (fileStream.good())
        {
            // Store the next word in the file in a local variable.
            string word;
            fileStream >> word;

            //Look if it's already there.
            if (wordsCount.find(word) == wordsCount.end()) // Then we've encountered the word for a first time.
                wordsCount[word] = 1; // Initialize it to 1.
            else // Then we've already seen it before..
                wordsCount[word]++; // Just increment it.
        }
    else  // We couldn't open the file. Report the error in the error stream.
    {
        cerr << "Couldn't open the file." << endl;
    }

    // Print the words map.
    PrintMap(wordsCount);
}

Answer 1

您可以使用带有 std::ctype<char> 的流小平面imbue() ed 将您喜欢的任何字符视为空间。这样做看起来像这样:

#include<locale>
#include<cctype>

struct myctype_table {
    std::ctype_base::mask table[std::ctype<char>::table_size];
    myctype_table(char const* spaces) {
        while (*spaces) {
            table[static_cast<unsigned char>(*spaces)] = std::ctype_base::isspace;
        }
    }
};
class myctype
    : private myctype_table,
    , public std::ctype<char> {
public:
    myctype(char const* spaces)
        : myctype_table(spaces)
        , std::ctype<char>(table) {
    };
};

int main() {
     std::locale myloc(std::locale(), new myctype(" \t\n\r?:.,!"));
     std::cin.imbue(myloc);
     for (std::string word; std::cin >> word; ) {
         // words are separated by the extended list of spaces
     }
}

此代码目前未测试 - 我正在移动设备上输入。我可能误用了一些 std::cypte<char>接口(interface)，但在修复名称等之后沿着这些方向的东西应该可以工作。