How to use C++ String Streams to append int?

问题

could anyone tell me or point me to a simple example of how to append an int to a stringstream containing the word "Something" (or any word)?

回答1:

stringstream ss;
ss << "Something" << 42;

For future reference, check this out.

http://www.cplusplus.com/reference/iostream/stringstream/

回答2:

I'd probably do something on this general order:

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

int main() {      
    std::stringstream stream("Something ");

    stream.seekp(0, std::ios::end);
    stream << 12345;

    std::cout << stream.str();
    return 0;
}

With a normal stream, to add to the end, you'd open with std::ios::ate or std::ios::app as the second parameter, but with string streams, that doesn't seem to work dependably (at least with real compilers -- neither gcc nor VC++ produces the output I'd expect when/if I do so).

回答3:

If you are already using boost, it has lexical_cast that can be be used for this. It is basically a packaged version of the above, that works on any type that can be written to and read from a stream.

string s("something");

s += boost::lexical_cast<string>(12);

Its probably not worth using if you aren't using boost already, but if you are it can make your code clearer, especially doing something like

foo(string("something")+boost::lexical_cast<string>(12));

来源：https://stackoverflow.com/questions/2066184/how-to-use-c-string-streams-to-append-int