ctype、字符串和容器

ctype facet函数( is , scan_is , scan_not 仅支持纯字符指针,而不支持基于迭代器的容器,如std::string甚至std::vector。。。 然后可以写:

const ctype<char>& myctype = use_facet<std::ctype<char> >(locale(""));
string foo_str = "hi there here is a number: 748574 and text again";
vector<char> foo(foo_str.begin(),foo_str.end());

//then one could write

vector<char>::iterator num_begin_it = myctype.scan_is( ctype<char>::digit, foo.begin(), foo.end() );
vector<char> foo_num_1( foo, num_begin_it, myctype.scan_not(ctype<char>::digit, num_begin_it, foo.end() );

//instead of:
const char* num_begin_pc = myctype.scan_is(ctype<char>::digit, &foo[0], &foo[foo.size()-1]+1); // &foo[foo.size()-1]+1) instead of foo.end() is not quite readable.
vector<char> foo_num_2(num_begin_pc, myctype.scan_not(ctype<char>::digit, num_begin_pc, &foo[foo.size()-1]+1));

//appendix:
//STL/Boost solution, even more verbose:

function<bool(char)> is_digit_func =
    bind(
        mem_fn(static_cast<bool (ctype<char>::*)(ctype<char>::mask,char) const>(&ctype<char>::is)),
        &myctype,
        ctype<char>::digit,
        _1
    );
vector<char>::iterator num_begin_0x = find_if(foo.begin(), foo.end(),is_digit_func);
vector<char> foo_num_3(num_begin_0x,find_if(num_begin_0x, foo.end(),not1(is_digit_func)));

// all 3 foo_num_X will now contain "748574"

有没有更好的(=不太详细)方法可以将ctype函数与基于迭代器的容器一起使用?

如果不需要的话,STL/Boost解决方案就可以了

copy_if 标准库中的算法,但我已经 reason for this .