内联替换 std::stringstream 中的字符

Question

我想知道是否可以使用 std::replace 将字符串流中的双引号替换为单引号。

我有：

std::replace(
    std::ostreambuf_iterator<char>(ssScript),
    std::ostreambuf_iterator<char>(),
    '"', '\''
);

当然 ostreambuf_iterator 没有默认构造函数，因此无法编译。

是否有另一种方法来替换像这样的内联字符串流中出现的字符？

Answer 1

std::stringstream class 提供了一个用于操作流的接口，而不是它的内容。要操作流的内容，您必须获取字符串，对其进行操作，然后将字符串放入流中，如下所示：

#include <iostream>
#include <sstream>
#include <algorithm>
#include <string>

int main(void)
{
    std::stringstream ss;
    ss << "\"this is a string in a stream\"";
    std::cout << "Before: " << ss.str() << std::endl;
    std::string s = ss.str();
    std::replace(s.begin(), s.end(), '"', '\'');
    ss.str(s);
    std::cout << "After: " << ss.str() << std::endl;
    return 0;
}

你得到：

Before: "this is a string in a stream"
After: 'this is a string in a stream'

Answer 2

假设字符串的生成器在生成字符串时仅使用 stringstream 的 ostream 接口，则有可能（一旦你破译了文档，实际上很容易）构建一个自定义的 ostream，它既可以过滤又可以附加到您可以完全访问的字符串。

示例：

#include <boost/iostreams/device/back_inserter.hpp>
#include <boost/iostreams/filtering_stream.hpp>
#include <iostream>
#include <string>

namespace io = boost::iostreams;

// a custom filter
struct replace_chars
{
    typedef char                   char_type;
    typedef io::output_filter_tag  category;


    replace_chars(char_type from, char_type to) : from(from), to(to) {}

    template<typename Sink>
    bool put(Sink& snk, char_type c)
    {
        if (c == from) c = to;
        return io::put(snk, c);
    }

    char_type from, to;
};

// some code that writes to an ostream    
void produce_strings(std::ostream& os)
{
    os << "The quick brown fox called \"Kevin\" jumps over the lazy dog called \"Bob\"" << std::endl;
    os << "leave 'these' as they are" << std::endl;
    os << "\"this\" will need to be flushed as there is no endl";
}

// test
int main()
{
    // a free buffer to which I have access
    std::string buffer;

    // build my custom ostream    
    io::filtering_ostream stream;
    stream.push(replace_chars('"', '\''));   // stage 1 - filter
    stream.push(io::back_inserter(buffer));  // terminal stage - append to string

    // pass the ostream interface of my filtering, string-producing stream    
    produce_strings(stream);
    // flush in case the callee didn't terminal with std::endl
    stream.flush();

    std::cout <<buffer <<std::endl;
}

预期输出：

The quick brown fox called 'Kevin' jumps over the lazy dog called 'Bob'
leave 'these' as they are
'this' will need to be flushed as there is no endl

内联替换 std::stringstream 中的字符

replacing chars in std::stringstream inline

c++

replace

stringstream