How can I clear console

Question

As in the title. How can I clear console in C++?

Answer 1

outputting multiple lines to window console is useless..it just adds empty lines to it. sadly, way is windows specific and involves either conio.h (and clrscr() may not exist, that's not a standard header either) or Win API method

#include <windows.h>

void ClearScreen()
  {
  HANDLE                     hStdOut;
  CONSOLE_SCREEN_BUFFER_INFO csbi;
  DWORD                      count;
  DWORD                      cellCount;
  COORD                      homeCoords = { 0, 0 };

  hStdOut = GetStdHandle( STD_OUTPUT_HANDLE );
  if (hStdOut == INVALID_HANDLE_VALUE) return;

  /* Get the number of cells in the current buffer */
  if (!GetConsoleScreenBufferInfo( hStdOut, &csbi )) return;
  cellCount = csbi.dwSize.X *csbi.dwSize.Y;

  /* Fill the entire buffer with spaces */
  if (!FillConsoleOutputCharacter(
    hStdOut,
    (TCHAR) ' ',
    cellCount,
    homeCoords,
    &count
    )) return;

  /* Fill the entire buffer with the current colors and attributes */
  if (!FillConsoleOutputAttribute(
    hStdOut,
    csbi.wAttributes,
    cellCount,
    homeCoords,
    &count
    )) return;

  /* Move the cursor home */
  SetConsoleCursorPosition( hStdOut, homeCoords );
  }

For POSIX system it's way simpler, you may use ncurses or terminal functions

#include <unistd.h>
#include <term.h>

void ClearScreen()
  {
  if (!cur_term)
    {
    int result;
    setupterm( NULL, STDOUT_FILENO, &result );
    if (result <= 0) return;
    }

  putp( tigetstr( "clear" ) );
  }

Answer 2

Here is a simple way to do it:

#include <iostream>

using namespace std;

int main()
{
    cout.flush(); // Flush the output stream
    system("clear"); // Clear the console with the "system" function
}

Answer 3

This is REALLY choppy but try:

void cls() {
    for (int i = 0; i < 250; ++i) {
        std::cout << endl;
    }
}

Answer 4

Use System::Console::Clear();

This will clear (empty) the buffer

Answer 5

In Windows:

#include <cstdlib>

int main() { 
    std::system("cls");
    return 0;
}

In Linux/Unix:

#include <cstdlib>

int main() { 
    std::system("clear");
    return 0;
}

Answer 6

For Windows, via Console API:

void clear() {
    COORD topLeft  = { 0, 0 };
    HANDLE console = GetStdHandle(STD_OUTPUT_HANDLE);
    CONSOLE_SCREEN_BUFFER_INFO screen;
    DWORD written;

    GetConsoleScreenBufferInfo(console, &screen);
    FillConsoleOutputCharacterA(
        console, ' ', screen.dwSize.X * screen.dwSize.Y, topLeft, &written
    );
    FillConsoleOutputAttribute(
        console, FOREGROUND_GREEN | FOREGROUND_RED | FOREGROUND_BLUE,
        screen.dwSize.X * screen.dwSize.Y, topLeft, &written
    );
    SetConsoleCursorPosition(console, topLeft);
}

It happily ignores all possible errors, but hey, it's console clearing. Not like system("cls") handles errors any better.

For *nixes, you usually can go with ANSI escape codes, so it'd be:

void clear() {
    // CSI[2J clears screen, CSI[H moves the cursor to top-left corner
    std::cout << "\x1B[2J\x1B[H";
}

Using system for this is just ugly.