How can I free ostringstream?

Question

I have following code:

int n=2;
ostringstream convert;   // stream used for the conversion
convert << n; 
string query= convert.str();

reduplicate question？ http://stackoverflow.com/questions/5288036/how-to-clear-ostringstream ？ — bystander, Feb 13 '13 at 10:23
@bystander: What's that weird question mark? Are you making a homograph attack? — Kerrek SB, Feb 13 '13 at 10:39

score 4 · Accepted Answer · answered Feb 13 '13 at 10:21

With lifetime management:

std::string query;
int n = 2;

{
    std::ostringstream oss;
    oss << n;
    query = oss.str();
}

Shorter, but a bit tougher to read:

int n = 2;
std::string query
          = static_cast<std::ostringstream &>(std::ostringstream() << n).str();

Possibly better, depending on your situation:

auto query = std::to_string(2);

score 0 · Answer 2 · answered Feb 13 '13 at 10:22

0

Just let it go out of scope:

int n=2;
string query;
{
    ostringstream convert;
    convert << n;
    query = convert.str();
}

answered Feb 13 '13 at 10:22

Michael Wild

24,977
3
43
43

score 0 · Answer 3 · answered Feb 13 '13 at 10:23

0

you don't need to free the stream. the stream is on the stack, so it will destroyed automatically.

answered Feb 13 '13 at 10:23

peterus

15
5

score 0 · Answer 4 · answered Feb 13 '13 at 10:38

How can I free ostringstream?

If by "free" you mean "deallocate resources" for the instance, then let it go out of scope.

int n=2;
string query;
{
    ostringstream convert;   // stream used for the conversion
    convert << n; 
    qyuery = convert.str();
}

If you mean "clear the contents" then you can use:

int n=2;
ostringstream convert;   // stream used for the conversion
convert << n; 
string query1 = convert.str();
// clear the contents & reset error bits (thanks @PeterWood)
convert.str("");
convert.clear();
convert << n + 1;
string query2 = convert.str();

How can I free ostringstream?

4 Answers4