Limpar a tela

Há três formas de limpar a tela em um aplicativo de console.

Exemplo 1

O primeiro método consiste em configurar o aplicativo para sequências de saída de terminal virtual e, em seguida, chamar o comando "limpar tela".

#include <windows.h>

int main(void)
{
    HANDLE hStdOut;

    hStdOut = GetStdHandle(STD_OUTPUT_HANDLE);

    // Fetch existing console mode so we correctly add a flag and not turn off others
    DWORD mode = 0;
    if (!GetConsoleMode(hStdOut, &mode))
    {
        return ::GetLastError();
    }

    // Hold original mode to restore on exit to be cooperative with other command-line apps.
    const DWORD originalMode = mode;
    mode |= ENABLE_VIRTUAL_TERMINAL_PROCESSING;

    // Try to set the mode.
    if (!SetConsoleMode(hStdOut, mode))
    {
        return ::GetLastError();
    }

    // Write the sequence for clearing the display.
    DWORD written = 0;
    PCWSTR sequence = L"\x1b[2J";
    if (!WriteConsoleW(hStdOut, sequence, (DWORD)wcslen(sequence), &written, NULL))
    {
        // If we fail, try to restore the mode on the way out.
        SetConsoleMode(hStdOut, originalMode);
        return ::GetLastError();
    }

    // To also clear the scroll back, emit L"\x1b[3J" as well.
    // 2J only clears the visible window and 3J only clears the scroll back.

    // Restore the mode on the way out to be nice to other command-line applications.
    SetConsoleMode(hStdOut, originalMode);

    return 0;
}

Você pode encontrar variações adicionais sobre esse comando na documentação de sequências de terminal virtual em Apagar na tela.

Exemplo 2

O segundo método consiste em escrever uma função para rolar o conteúdo da tela ou buffer e definir um preenchimento para o espaço revelado.

Esse método corresponde ao comportamento do prompt de comando cmd.exe.

#include <windows.h>

void cls(HANDLE hConsole)
{
    CONSOLE_SCREEN_BUFFER_INFO csbi;
    SMALL_RECT scrollRect;
    COORD scrollTarget;
    CHAR_INFO fill;

    // Get the number of character cells in the current buffer.
    if (!GetConsoleScreenBufferInfo(hConsole, &csbi))
    {
        return;
    }

    // Scroll the rectangle of the entire buffer.
    scrollRect.Left = 0;
    scrollRect.Top = 0;
    scrollRect.Right = csbi.dwSize.X;
    scrollRect.Bottom = csbi.dwSize.Y;

    // Scroll it upwards off the top of the buffer with a magnitude of the entire height.
    scrollTarget.X = 0;
    scrollTarget.Y = (SHORT)(0 - csbi.dwSize.Y);

    // Fill with empty spaces with the buffer's default text attribute.
    fill.Char.UnicodeChar = TEXT(' ');
    fill.Attributes = csbi.wAttributes;

    // Do the scroll
    ScrollConsoleScreenBuffer(hConsole, &scrollRect, NULL, scrollTarget, &fill);

    // Move the cursor to the top left corner too.
    csbi.dwCursorPosition.X = 0;
    csbi.dwCursorPosition.Y = 0;

    SetConsoleCursorPosition(hConsole, csbi.dwCursorPosition);
}

int main(void)
{
    HANDLE hStdout;

    hStdout = GetStdHandle(STD_OUTPUT_HANDLE);

    cls(hStdout);

    return 0;
}

Exemplo 3

O terceiro método consiste em escrever uma função para limpar programaticamente a tela com uso das funções FillConsoleOutputCharacter e FillConsoleOutputAttribute.

O código de exemplo a seguir demonstra essa técnica.

#include <windows.h>

void cls(HANDLE hConsole)
{
    COORD coordScreen = { 0, 0 };    // home for the cursor
    DWORD cCharsWritten;
    CONSOLE_SCREEN_BUFFER_INFO csbi;
    DWORD dwConSize;

    // Get the number of character cells in the current buffer.
    if (!GetConsoleScreenBufferInfo(hConsole, &csbi))
    {
        return;
    }

    dwConSize = csbi.dwSize.X * csbi.dwSize.Y;

    // Fill the entire screen with blanks.
    if (!FillConsoleOutputCharacter(hConsole,        // Handle to console screen buffer
                                    (TCHAR)' ',      // Character to write to the buffer
                                    dwConSize,       // Number of cells to write
                                    coordScreen,     // Coordinates of first cell
                                    &cCharsWritten)) // Receive number of characters written
    {
        return;
    }

    // Get the current text attribute.
    if (!GetConsoleScreenBufferInfo(hConsole, &csbi))
    {
        return;
    }

    // Set the buffer's attributes accordingly.
    if (!FillConsoleOutputAttribute(hConsole,         // Handle to console screen buffer
                                    csbi.wAttributes, // Character attributes to use
                                    dwConSize,        // Number of cells to set attribute
                                    coordScreen,      // Coordinates of first cell
                                    &cCharsWritten))  // Receive number of characters written
    {
        return;
    }

    // Put the cursor at its home coordinates.
    SetConsoleCursorPosition(hConsole, coordScreen);
}

int main(void)
{
    HANDLE hStdout;

    hStdout = GetStdHandle(STD_OUTPUT_HANDLE);

    cls(hStdout);

    return 0;
}