When trying to concatenate a string in ostringstream, which string contents are modified and reconstructed, string get added at beginning [duplicate]

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Closed 8 years ago.

Possible Duplicate:
What is the purpose of ostringstream's string constructor?

I am facing below issue. I have an ostringstream say testStr. I first insert few characters inside it using <<

testStr << somechar;

Then I modified:

testStr.Str("some string")

so that now testStr is containing "Some String"

Now I want to add some characters(say " " and "TEST") at the end so that it can become "Some String TEST".

testStr << " " << "TEST";

But I am getting " TESTString". Please let me know what can be done?

Adding sample code:

#include <iostream>
#include <sstream>
int main() {
  std::ostringstream s;
  s << "Hello";
  s.str("WorldIsBeautiful");
  s << " " << "ENDS";
  std::cout << s.str() << std::endl;

}

Output is " ENDSIsBeautiful" where as I expected "WorldIsBeautiful ENDS".

Answer 1

I'm not overly sure, but it looks like it's still set to write at the beginning. To fix this, you can call s.seekp(0, std::ios_base::end); to set the output position indicator back to the end. I have a working sample here:

#include <iostream>
#include <sstream>

int main() {
  std::ostringstream s;
  s.str( "Hello" );
  s.seekp(0, std::ios_base::end);
  s << "x" << "World";
  std::cout << s.str() << std::endl;
}

Output:

HelloxWorld