// This small program can plot many functions. // It can theoretically plot functions of any degree. // Input is formatted as follows: // Line 1: n, the number of functions to plot. // Lines 2..n: coefficients a, b, c, ... for each function. // Leave it empty for the sample trintic/cubic function. // There is a more complex sample input in my comment. import java.util.ArrayList; import java.util.Collections; import java.util.List; import java.util.Arrays; import java.util.Scanner; public class Main { private static ArrayList cfs = new ArrayList<>(); private static FunctionPlotter plane = new FunctionPlotter(cfs); private static Scanner sc = new Scanner(System.in); private static int functions = 1; private static void getAndPlot() { // Plot each function as the user enters them. for (var i = 1; i <= functions; ++i) { try { System.out.print("Enter the coefficients for " + ((functions > 1) ? "function #" + i + ": " : "the function: ")); // Get new coefficients. cfs.clear(); for (var token : sc.nextLine().split("\\s++")) { cfs.add(Double.parseDouble(token)); } } catch (Exception e) { cfs.addAll(Arrays.asList(0.125, 1.0, 0.5, 0.0)); } // Set new coefficients and plot. plane.cfs = cfs; plane.plot(i); } } public static void main(String[] args) { try { System.out.print("Enter the number of functions to plot: "); functions = Integer.parseInt(sc.nextLine()); } catch (Exception ignored) {} getAndPlot(); System.out.println("Truncated graph of " + ((functions > 1) ? "multiple functions:\n" : "the function:\n")); plane.printPlane(); sc.close(); } } class FunctionPlotter { private static final int SIZE = 40; private final String[] FUNC_CHARS = "x@%0*$#?".split(""); private int[][] plane = new int[SIZE][SIZE]; // Coefficients of the current function. ArrayList cfs; FunctionPlotter(ArrayList cfs) { this.cfs = cfs; } private int calculate(double x) { var sum = 0.0; for (var i = 0; i < cfs.size(); ++i) { sum += cfs.get(i) * Math.pow(x, cfs.size() - 1 - i); } return (int) Math.round(sum); } private void flipPlane() { var temp = new ArrayList<>(List.of(plane)); Collections.reverse(temp); temp.toArray(plane); } private void printYAxisAndPoints() { // Current y-axis coordinate. var s = SIZE / 2 - 1; System.out.println(" ^"); for (var i : plane) { // Display current y-axis coordinate. System.out.printf(((s < 0) ? "" : " ") + "%-3s" + ((s < 0) ? " " : "") + "|", s--); // Plot points. for (var e : i) { System.out.print(e < 1 ? " " : FUNC_CHARS[e - 1]); } System.out.println(); } } void plot(int c) { int y; // Plot points, rounding decimal coordinates to the nearest integer. for (var i = -SIZE / 2; i < SIZE / 2; ++i) { y = calculate(i); // Plot if the point lies within the range of the plane. if (y >= -SIZE / 2 && y < SIZE / 2) { plane[y + SIZE / 2][i + SIZE / 2] = c; } } } void printPlane() { // Flip the plane as array indices are opposite to plane coordinates. flipPlane(); printYAxisAndPoints(); // Display x-axis line. System.out.print(" +"); for (var ignored : plane) { System.out.print("-"); } System.out.print(">\n "); // Display x-axis numbers with an interval of five. for (var i = -(SIZE / 2); i < SIZE / 2; i += 5) { System.out.printf("%-5d", i); } // Unflip plane to allow for more plotting. flipPlane(); } }

[JV] Function Plotter