Formatting: how to convert 1 to “01”, 2 to “02”, 3 to "03", and so on

Question

Following code outputs the values in time format, i.e. if it's 1:50pm and 8 seconds, it would output it as 01:50:08

cout << "time remaining: %02d::%02d::%02" << hr << mins << secs;

But what I want to do is (a) convert these ints to char/string (b) and then add the same time format to its corresponding char/string value.

I have already achieved (a), I just want to achieve (b).

e.g.

    char currenthour[10] = { 0 }, currentmins[10] = { 0 }, currentsecs[10] = { 0 };

    itoa(hr, currenthour, 10);
    itoa(mins, currentmins, 10);
    itoa(secs, currentsecs, 10);

Now if I output 'currenthour', 'currentmins' and 'currentsecs', it will output the same example time as, 1:50:8, instead of 01:50:08.

Ideas?

Answer 1

If you don't mind the overhead you can use a std::stringstream

#include <sstream>
#include <iomanip>

std::string to_format(const int number) {
    std::stringstream ss;
    ss << std::setw(2) << std::setfill('0') << number;
    return ss.str();
}