Plot a Sinewave to the Console

Nice demo idea, vegaseat. A couple of gotchas that tripped up vallerie joy and others are worth calling out:

• If you call SetPixel, you must link against Gdi32 and draw to a valid HDC (for example, from a real window’s paint routine). Linking errors like “undefined reference to __imp_SetPixel” usually mean the GDI library was not linked. In Visual Studio add Gdi32.lib to Linker -> Input, and with MinGW link with -lgdi32. Also note SetPixel requires a device context and will not persist reliably if you try to draw directly on the console window. (learn.microsoft.com, sourceforge.net)

• kal_crazy’s Unicode/MBCS tip is on point. Alternatively, keep the project in Unicode and use the generic-text macros (TEXT(), TCHAR, etc.) so your code compiles cleanly in either setting. New Windows code should prefer Unicode. (learn.microsoft.com)

If you truly want a console-only plot (no GDI, no linking headaches), render an ASCII sine in a text buffer and print it:

#include <iostream>
#include <vector>
#include <cmath>

int main() {
    const int width = 80, height = 25;
    const double twoPi = 6.283185307179586, cycles = 2.0;
    std::vector<std::string> buf(height, std::string(width, ' '));
    const int mid = height / 2, amp = height / 2 - 2;

    for (int x = 0; x < width; ++x) {
        double t = cycles * twoPi * x / (width - 1);
        int y = mid - static_cast<int>(std::lround(amp * std::sin(t)));
        if (0 <= y && y < height) buf[y][x] = '*';
    }
    for (int x = 0; x < width; ++x) buf[mid][x] = (buf[mid][x] == '*') ? '*' : '-';
    for (const auto& row : buf) std::cout << row << "\n";
}

Sticking with GDI? For performance, avoid per-pixel calls where possible; draw a Polyline, or at least prefer SetPixelV over SetPixel. It is a faster variant and avoids returning the previous color. (learn.microsoft.com)

For completeness, if you want to manipulate the console screen buffer directly (characters and colors), look at WriteConsoleOutputCharacter and friends. (learn.microsoft.com)