Question

I need to get the date and month in two digit format. But instead of using setw all the time, is there a single setting to say that set every field to minimum ‘x’ length.

void getDate(std::string& m_resultDate)
{

    time_t curTime;
    struct tm *curTimeInfo;
    std::stringstream sCurDateTime(std::stringstream::out | std::stringstream::in);

    time(&curTime);
    curTimeInfo = localtime(&curTime);

    sCurDateTime.width(4);
    sCurDateTime.fill('0');

    sCurDateTime << ( curTimeInfo->tm_year + 1900 );
    sCurDateTime.width(2);
    sCurDateTime.fill('0');

    sCurDateTime << ( curTimeInfo->tm_mon) ;

    sCurDateTime.width(2);
    sCurDateTime.fill('0');
    sCurDateTime << ( curTimeInfo->tm_mday) ;

    m_resultDate = sCurDateTime.str();

}

Answer 1

Iostreams are fickle, and you cannot really rely on the various formatting flags to persist. However, you can use <iomanip> to write things a bit more concisely:

#include <iomanip>
using namespace std;
o << setw(2) << setfill('0') << x;

Modifiers like o << hex and o << uppercase usually persist, while precision and field width modifiers don’t. Not sure about the fill character.