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Please i kind of need a quick help on how to plot polynomial graphs using c++.

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asked how to plot polynomial graphs in C++. correctly suggested showing existing code, and pointed out a quick external option (gnuplot). Below is a compact, practical workflow for a pure C++ solution plus a few cautions and quick tips that remain useful even years later.

A minimal approach (pure C++): sample x values across the domain, evaluate the polynomial using Horner's method for stability, map (x,y) to pixel coordinates, draw straight segments between successive samples, and save as a simple image (PPM) or display with a lightweight graphics library. This is fast to implement and easy to debug.

Example pieces (concise):

double eval_poly(const std::vector<double>& a, double x) {
    double y = 0.0;
    for (int i = (int)a.size() - 1; i >= 0; --i) y = y*x + a[i];
    return y;
}

int to_px(double x,double xmin,double xmax,int w){
    return int((x-xmin)/(xmax-xmin)*(w-1));
}
int to_py(double y,double ymin,double ymax,int h){
    return h-1-int((y-ymin)/(ymax-ymin)*(h-1));
}

Troubleshooting and tips: use a pre-scan to estimate ymin/ymax or compute extrema numerically for better framing; increase sample density where curvature is high to avoid jagged lines; rescale x to [-1,1] before evaluation for high-degree polynomials; use long double for extra precision or switch to a plotting library if higher quality rendering (anti-aliasing, axes, labels) is needed. For fast prototyping, piping data to gnuplot (as suggested) is often the quickest route.

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Member Avatar for ~s.o.s~

Show some effort on your part by pasting the code you have so far got here...

Member Avatar for pty

Please i kind of need a quick help on how to plot polynomial graphs using c++.

http://www.gnuplot.info/

Have fun.

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