Use an Anonymous Stringstream to Construct a String

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I want to read directly into a string with code like this:

std::string myString(( std::ostringstream() << myInt << " "
                                            << myFloat << " "
                                            << std::boolalpha << myBool ).str());

But VS2012 is giving me a complaint that basic_ostream doesn't have an str() method.

Is there a way to do this with an anonymous stringstream?

Use an Anonymous Stringstream to Construct a String, Use an Anonymous Stringstream to Construct a String - c++. You need to use cast. static_cast<std::ostringstream&>(std::ostringstream() << etc).str()  If we look up the std::string docs, under "search" we can find the following functions that might be of relevance: . find(): This will find the first substring, starting at an index in the string.

basic_osstream::operator<< returns a basic_ostream, not a ostringstream. The compiler is not lying to you.

I would rather create a StringBuilder type device.

class StringBuilder
{
public:
    template <typename T> inline StringBuilder& operator<<(const T& t)
    {
        mStream << t;
        return * this;
    }
    inline std::string get() const
    {
        return mStream.str();
    }
    inline operator std::string () const
    {
        return get();
    }
private:
    std::stringstream mStream;
};

Now you can:

std::string myString (StringBuilder() << myInt << " " << myFloat /*...*/);

There are also similar devices in Boost -- you would do well to use those instead if it is available to you.

C++: using an anonymous stringstream to construct a string · Issue , As we'll see later in this section, this is a powerful way to make declarations about our You may have been wondering why the anonymous goroutine completes Println contains a pull from the channel stringStream and will sit there until a  Length of the substring to be copied (if the string is shorter, as many characters as possible are copied). A value of string::npos indicates all characters until the end of str. s Pointer to an array of characters (such as a c-string). n Number of characters to copy. c Character to fill the string with.

I had this problem too, and John answer seems fine, thanks a lot! - I tried to build a string by using the operator '<<' onto a 'stringstream', and it did compiled & worked fine with 'clang' on macOS but not with 'gcc' on ubuntu, (compiling with -std=c++11 on modern updated compilers), it looks like in the Mac machine the operator is returning a stringstream instead of a basic_ostream......

Here is a minimal program which does not compiles with g++ but compiles with clang (experimental concepts), as tested in the Compiler Explorer (godbolt.org):

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

int main()
{
   using namespace std;
   cout << ((stringstream() << "hola").str()) << endl ;
}

Concurrency in Go: Tools and Techniques for Developers, In the third example, we use WITH-OUTPUT-TO-STRING with only one argument. In this case, the macro will create an “anonymous” string for us, which'll 5-7).17 Now this particular string will be used as the sink of the string stream and the  It is common to convert string to int and int to string in C++ programs. This post introduces how to convert a valid string to int and int to string in C++ using C and C++ ways and libraries. If your string is not a valid integer string, you should check it first or use other methods.

Common Lisp Recipes: A Problem-Solution Approach, This guide shows you a lot of tools for building strings in C++, from the simple The most simple way to concatenate strings in C++ is by using the + (or +=) operator: And when called on its str() method, the ostringstream produces the file to std::string object 'fileContents' in memory. using an unnamed  Namespace-scope anonymous unions must be declared static unless they appear in an unnamed namespace. Union-like classes. A union-like class is either a union, or a (non-union) class that has at least one anonymous union as a member. A union-like class has a set of variant members: the non-static data members of its member anonymous unions;

Strings In C++, (2) initialization constructor: Constructs a stringstream object with a copy of str as In any case, both objects have internal string buffers that use independent  I will give you the simple code. Basiclly, you store the string in string data type (or stringstream data type, whichever you like, I used string) and the check for whitespace and when they occur, print the word and store the initial. Here it is: #include <iostream> #include <string> using namespace std; int main() {string FullName, Initials

The Complete Guide to Building Strings In C++: From "Hello World , Converting a number to a string takes two steps using stringstreams: Here is constructed an unnamed stringstream object and performed the  use for loops in C++ to construct a program that displays a pyramid of Xs on the screen. The pyramid should look like: x xxx xxxxx xxxxxxx xxxxxxxxx It should perfectly look like Egyptian pyramid. I aligned Xs like that but in preview it doesn't show proper alignment of Xs. So ignore the pyramid shown in question area, just imagine a pyramid in your mind. (First X should be at center, second

Comments
  • This code compiles as-is and runs fine on Clang. (Apple LLVM version 5.0 (clang-500.2.79) (based on LLVM 3.3svn))
  • The non-member overloads cannot be used for the first <<. After that, you have the ostream& (non-const) which was returned by the first <<. The usual solution is to start with std::ostringstream().flush() << .... ostream::flush is a member function which returns a ostream&, and of course, it won't actually do anything on a stream which you haven't yet written to.
  • @JamesKanze: I just came to know that there C++11 behaves differently in this case. So what I described before is true for C++03 only. With C++11, we don't need flush() trick anymore!
  • I seem to remember the same thing, but I can't find what has changed in the standard. (I think it is somehow related to rvalue-references; I don't know why.)
  • @JamesKanze: Yes, 27.7.3.9 has introduced rvalue-references for output streams (and there is rvalue-references for input streams also).
  • @Nawaz I know that to Microsoft the standard is kind of a suggestion, but in Visual Studio 2010 I see your C++11 code work. I thought that Visual Studio 2010 was C++03?
  • FWIW: this would be my solution as well.
  • What is the similar device in boost. Am looking for it myself.