Question

I want to build a string label with a changing suffix. This is to take place within a for-loop. (The suffix being the value that is looped through). This is how I’d do it in C – is there a more c++-ish way to do this?

for (int i = 0; i<10; i++)
{
    char label[256];

    sprintf(label, "Label_no_%d", i);

    // convert label to a c plus plus string

    // Do stuff with the string here
}

Answer 1

You can use stringstreams:

for (int i = 0; i<10; i++)
{
    std::ostringstream label;

    label << "Label_no_" << i;

    // use label.str() to get the string it built
}

These let you use operator<<, exactly like you would for std::cout or a file, but writing to an in memory string instead.

Or alternatively you can use Boost.Format, which behaves more like sprintf with a C++ interface.