How do I use iomanip's setw, setfill, and left/right? Setfill isn't stopping its output

user3448821 picture user3448821 · Mar 26, 2014 · Viewed 40.2k times · Source

I'm trying to get my output to look like this:

size       time1       time2
-------------------------------
10         4           8
100        48          16
1000       2937        922
10000      123011      3902
100000     22407380    830722

And I know I need to use setw(), setfill(), and left. However, my attempts keep giving me incorrect output. Here is one example of my code:

std::cout << "size" << std::setw(20) << "time" << std::setw(20) << "time2\n";
std::cout << std::setfill('-') << std::setw(60) << "-" << std::endl;
run = 10;
for(int i = 0; i < 5; i++) {
    std::cout << run;
    run *= 10;
    std::cout << std::setw(20) << std::left << time1[i];
    std::cout << std::setw(20) << std::left << time2[i] << "\n";
}

And here's the output:

size    time1    time2
------------------------------------------------------------
103-------------------13------------------
100171-----------------199-----------------
100013183---------------667-----------------
10000670130--------------8205----------------
10000014030798-------------1403079888---------

I've tried changing the order that I'm using setw(), setfill(), and left, but I'm just flying blind right now. I've also searched iomanip tutorials. I'm following the directions--as far as I can tell--but I'm still not getting it.

How do I stop the setfill() from running over? How do I justify left but use setw() to stop the numbers from running into each other?

Answer

sj0h picture sj0h · Mar 26, 2014

How about:

std::cout << "size" << std::setw(20) << "time" << std::setw(20) << "time2\n";
std::cout << std::setfill('-') << std::setw(60) << "-" << std::endl;
run = 10;
std::cout << std::setfill(' ');  //fill with spaces
for(int i = 0; i < 5; i++) {
    std::cout << std::setw(20) << std::left << run;  // fill the run column
    run *= 10;
    std::cout << std::setw(20) << std::left << time1[i];
    std::cout << std::setw(20) << std::left << time2[i] << "\n";
}