Thread: stringstream + iomanip

Code:

stringstream Output;

...

Output << setfill('0') << setw(pooldigits);

Despite the above line, int values are not being padded. I've checked that the value of pooldigits is 3, just before the above line, and even tried specifying everything manually, as such.

Code:

Output.fill('0');
Output.width(3);

Output << 0 << endl;

Even with the above code, Output is coming up with "0", instead of "000".

Is there some inclusion or linking item I'm missing, or have I intermittently done something elsewhere in my code to break it? Has anyone encountered something similar before? I'll post more code if you guys need it, but this file alone is over a hundred lines.

Thanks in advance!

~ Jake

What you have should work. Are you sure you're correctly compiling and executing the code? A common occurrence when things are not as they seem is that the program is edited, not recompiled, and therefore an older version of the executable is run.

I've narrowed it down a bit more, by commenting out everything else in the same scope as this particular stringstream item. I've discovered the following...

Code:

  Output.fill('0');
  Output.width(pooldigits);

  Output << 0 << endl;

Correctly gives "000", but...

Code:

  Output.fill('0');
  Output.width(pooldigits);

  Output << "ip dhcp pool " << 0 << endl;

...doesn't. Do these modifiers have a one-time-use limit?

And yes, I've made sure I'm using the right files.

Originally Posted by Jaken Veina

Do these modifiers have a one-time-use limit?

Generally, yes. When the value being formatted using those modifiers is output, the stream reverts to default state.

Actually, no. setw() is the only one that is auto-reset, all others keep their state.

I had that feeling several times and I kept looking at the documentation for a hint that this was the case, but there doesn't seem to be any there. Adding setw() before every item that needs to be padded certainly does it. Thanks for the help.

~ Jake