单变量多项式（来自文本文件）
我想修改下面的代码来从文本文件中读取节点（与硬编码值相比）
此外，从文本文件中读取数据的格式为：
P1 = 3 5 1 -1 0 8
P2 = 5 6 2 -1 1 7 0 -4
等等…
将值命名为P（x）并输入剩余数据。 任何建议？
import java.io.DataInputStream; import java.util.LinkedList; import java.util.ListIterator; // A term contains the coefficient and the exponent of x. class Term { public Term(int c, int d) { coeff = c; degree = d; } public Term multiply(Term other) { return new Term(coeff * other.coeff, degree + other.degree); } public void add(int c) { coeff += c; } public void sub(int c) { coeff -= c; } public int getCoeff() { return coeff; } public int getDegree() { return degree; } private int coeff; private int degree; } // A polynomial made up of terms. class Polynomial { // Construct a Polynomial object. public Polynomial() { terms = new LinkedList(); } public Polynomial add(Polynomial p) { Polynomial r = new Polynomial(); ListIterator iterator = terms.listIterator(); while (iterator.hasNext()) { r.add((Term) iterator.next()); } ListIterator pIterator = p.terms.listIterator(); while (pIterator.hasNext()) { r.add((Term) pIterator.next()); } return r; } public Polynomial sub(Polynomial p) { Polynomial r = new Polynomial(); ListIterator iterator = terms.listIterator(); while (iterator.hasNext()) { r.sub((Term) iterator.next()); } ListIterator pIterator = p.terms.listIterator(); while (pIterator.hasNext()) { r.sub((Term) pIterator.next()); } return r; } public Polynomial multiply(Polynomial p) { Polynomial r = new Polynomial(); ListIterator iterator = terms.listIterator(); while (iterator.hasNext()) { ListIterator pIterator = p.terms.listIterator(); Term t1 = (Term) iterator.next(); while (pIterator.hasNext()) { Term t2 = (Term) pIterator.next(); r.add(t1.multiply(t2)); } } return r; } // Adds a coefficient and degree as a new Term. public void addTerm(int c, int d) { add(new Term(c, d)); } // Adds a term public void add(Term t) { int c = t.getCoeff(); int d = t.getDegree(); ListIterator iterator = terms.listIterator(); while (iterator.hasNext()) { Term current = (Term) iterator.next(); if (d == current.getDegree()) { if (c == -current.getCoeff()) iterator.remove(); else current.add(c); return; } else if (d < current.getDegree()) { iterator.previous(); iterator.add(t); return; } } iterator.add(t); } public void sub(Term t) { int c = t.getCoeff(); int d = t.getDegree(); ListIterator iterator = terms.listIterator(); while (iterator.hasNext()) { Term current = (Term) iterator.next(); if (d == current.getDegree()) { if (c == current.getCoeff()) iterator.remove(); else current.add(-c); return; } else if (d < current.getDegree()) { iterator.previous(); iterator.add(t); current.add(-c); return; } } iterator.add(t); } // Prints the polynomial. public void print() { ListIterator iterator = terms.listIterator(); while (iterator.hasNext()) { Term current = (Term) iterator.next(); if (current.getCoeff() != 0) { if ((current.getCoeff() 0) { System.out.print("x"); if (current.getDegree() > 1) System.out.print("^" + current.getDegree()); } } } System.out.println(); } @SuppressWarnings("deprecation") public char getChar() { char val = ' '; String buffer = ""; DataInputStream ds = new DataInputStream(System.in); try { buffer = ds.readLine(); val = buffer.charAt(0); } catch (Exception e) { } return (val); } public char enterNext() { System.out.println("Enter next Polynomial? "); char ans = this.getChar(); switch (ans) { case 'n': case 'N': System.out.println("All Done."); System.exit(0); break; case 'y': case 'Y': System.out.println("Enter next one, please!"); } return ans; } private LinkedList terms; } // A test program for Polynomial and Term classes. public class RPC { private static char ans = 'y'; public static void main(String[] args) { Polynomial p = new Polynomial(); do { p.addTerm(10, 0); p.addTerm(-1, 1); p.addTerm(9, 7); p.addTerm(5, 10); System.out.print("f(x) = "); p.print(); System.out.println(); Polynomial q = new Polynomial(); do { q.addTerm(1, 0); q.addTerm(-11, 1); q.addTerm(19, 7); q.addTerm(15, 10); System.out.print("q(x) = "); q.print(); p.enterNext(); } while (!(ans != 'y') | !(ans != 'Y')); System.out.println(); Polynomial a = p.add(q); System.out.print("f(x) + q(x) = "); a.print(); Polynomial s = p.sub(p); s.print(); Polynomial m = p.multiply(q); System.out.print("f(x) * q(x) = "); m.print(); System.exit(0); } while (ans != 1000); } } 除非您的数据已经是二进制forms，否则我不会使用DataInputStream 。 下面的示例使用BufferedReader来组成org.jscience.mathematics.function.Polynomial 。
请注意，最高阶系数首先是为了方便应用Horner方案 ，如本例所示。
1 2 3 4 4 3 2 1
系数：1 2 3 4 多项式：[1]x³+ [2]x²+ [3] x + [4] 系数：4 3 2 1 多项式：[4]x³+ [3]x²+ [2] x + [1]
码：
import java.io.BufferedReader; import java.io.FileReader; import java.io.IOException; import org.jscience.mathematics.function.Polynomial; import org.jscience.mathematics.function.Term; import org.jscience.mathematics.function.Variable; import org.jscience.mathematics.number.Integer64; /** @see http://stackoverflow.com/questions/8276150 */ public class ReadPoly { public static void main(String[] args) throws IOException { BufferedReader r = new BufferedReader(new FileReader("test.txt")); String s; while ((s = r.readLine()) != null) { System.out.println("Coefficient: " + s); Polynomial p = create(s.split(" ")); System.out.println("Polynomial: " + p); } } public static Polynomial create(String... a) { Variable x = new Variable.Local ("x"); Polynomial px = Polynomial.valueOf(Integer64.ZERO, x); for (int i = 0, e = a.length - 1; i < a.length; i++, e--) { px = px.plus(Polynomial.valueOf( Integer64.valueOf(a[i]), Term.valueOf(x, e))); } return px; } }