C++ how to overwrite a character in console, return carriage to start of line doesn't seem to work

Question

My question is, how do I get the numbers 10 - 0 to print out on the same line, overwriting each other using either a WIN32 or GNUC compiler in a simple manner like my code below:

This is what I have so far:

#include <iomanip>
#include <iostream>
using namespace std;

#ifdef __GNUC__
#include <unistd.h>
#elif defined _WIN32
#include <cstdlib>
#endif

int main()
{

  cout << "CTRL=C to exit...\n";

  for (int units = 10; units > 0; units--)
  {
    cout << units << '\r';
    cout.flush();
#ifdef __GNUC__
    sleep(1); //one second
#elif defined _WIN32
    _sleep(1000); //one thousand milliseconds
#endif

    //cout << "\r";// CR

  }

  return 0;
} //main

But this only prints:

10 9 8 7 6 5 4 3 2 1

No other libraries can be used but which I specify. There must be a way right? — CodingIsAwesome, Mar 28 '11 at 00:15
This is pretty much an exact duplicate of: http://stackoverflow.com/questions/5451826/easy-c-loop-with-pause-but-output-is-very-weird -- In the responses Midnighter gave you a decent suggestion of how to "back up" the output stream. — debracey, Mar 28 '11 at 00:28

score 4 · Accepted Answer · answered Mar 28 '11 at 00:20

I did some really trivial modification (mostly just to clean it up and make it more readable):

#include <iomanip>
#include <iostream>
using namespace std;

#ifdef __GNUC__
#include <unistd.h>
#define pause(n) sleep(n)
#elif defined _WIN32
#include <cstdlib>
#define pause(n) _sleep((n)*1000)
#endif

int main()
{

  cout << "CTRL=C to exit...\n";

  for (int units = 10; units > -1; units--)
  {
    cout << setw(2) << setprecision(2) << units << '\r';
    cout.flush();
    pause(1);
  }
  return 0;
}

This worked fine with both VC++ and Cygwin. If it's not working under mingw, it sounds to me like an implementation problem.

score 1 · Answer 2 · answered Mar 28 '11 at 00:14

1

I recommend you use ncurses or another library for this, there is no standarized way to do it.

answered Mar 28 '11 at 00:14

eordano

452
1
5
11

score 0 · Answer 3 · answered Mar 28 '11 at 00:22

0

Have you tried the backspace '\b' character?

answered Mar 28 '11 at 00:22

Ben Voigt

277,958
43
419
720

C++ how to overwrite a character in console, return carriage to start of line doesn't seem to work

3 Answers3