c++ - 替换C++字符串中的标点符号

Question

我试图理解为什么 binary_search() 找不到某些标点字符而 find() 找到了:

array<char, 25> punctuation_chars{'\'', '\"', ',', '.', ';', ':', '+', '*', '-', '_', '?', '!', '=', '|', '^', '/', '\\', '(', ')', '[', ']', '{', '}', '<', '>'};

bool is_punctuation(char c)
{
    auto ret = find(cbegin(punctuation_chars), cend(punctuation_chars), c) != cend(punctuation_chars);
    // auto ret = binary_search(cbegin(punctuation_chars), cend(punctuation_chars), c);
    if (c == ',')
        cout << c << " is" << (ret ? "" : " not") << " punctuation" << endl;
    return ret;
}

注释行不起作用(例如，for c == ',' 返回 false)，而 find 返回 cend(punctuation_chars)...

Answer 1

punctuation_chars 未排序，因此 std::binary_search 将不起作用。你需要调用 std::sort:

std::sort(std::begin(punctuation_chars), std::end(punctuation_chars));