Re: reading a file into std::string

From:
red floyd <no.spam.here@its.invalid>
Newsgroups:
comp.lang.c++
Date:
Mon, 08 Aug 2011 13:23:49 -0700
Message-ID:
<j1pgkl$q92$1@dont-email.me>
On 8/8/2011 7:05 AM, Sam wrote:

Sam writes:

arnuld writes:

I want to read a file into std::string. I am basically a C Programmer so
it was quite hard for me to understand how to do it in C++. I did C++
long time back (if you guys remember my name but I do remember Shiva and
Victor Bazarov and others).

I googled for it and this is the best what I could come up with. Do you
guys have any suggestion for improvement ? and whether this is really a
correct C++ program. (Compiled with "g++ -ansi -pedantic -Wall -Wextra")


Your program is basically a C program. Here's a C++ program.

#include <iostream>
#include <fstream>
#include <sstream>

int main()
{
std::ostringstream o;

o << std::ifstream("reference.cpp").rdbuf();

std::string my_contents= o.str();

return 0;
}


??? Or, here's a slightly more efficient version.

#include <iostream>
#include <fstream>
#include <iterator>
#include <algorithm>

int main()
{
std::string my_contents;

std::copy(std::istreambuf_iterator<char>(std::ifstream("reference.cpp").rdbuf()),

std::istreambuf_iterator<char>(),
std::back_insert_iterator<std::string>(my_contents));

return 0;
}


Avoid the copy.

#include <iostream>
#include <fstream>
#include <string>
#include <iterator>

int main()
{
    // note: extra parens on the constructor args to
    // avoid potential "Most Vexing Parse" issues
    std::string my_contents(
       std::istreambuf_iterator<char>(
          (std::ifstream("reference.cpp").rdbuf())),
          (std::istreambuf_iterator<char>()));
}

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