[Java]代码    

import java.util.*;    public class Nihe {     /**    * @param args    */   public static void main(String[] args) {    // TODO Auto-generated method stub    int n, m, i, j, k;    System.out.println("输入x的个数");    Scanner sc = new Scanner(System.in);    n = sc.nextInt();    double a[] = new double[n];    double b[] = new double[n];    System.out.println("输入x");    Scanner str1 = new Scanner(System.in);    for (i = 0; i < n; i++)     a[i] = str1.nextDouble();// 数组a存储x的值    System.out.println("输入y");    Scanner str2 = new Scanner(System.in);    for (i = 0; i < n; i++)     b[i] = str2.nextDouble();// 数组b存储y的值    double sumx = 0;    double sumy = 0;    for (i = 0; i < n; i++) {     sumx += a[i];// x的类和；     sumy += b[i];// y的类和；    }    // System.out.println("x的类和"+sumx);    // System.out.println("y的类和"+sumy);    System.out.println("输入拟合次数");    Scanner str3 = new Scanner(System.in);    m = str3.nextInt();    int s = 2 * m;    double Sumx[] = new double[s];    for (i = 0; i < s; i++) {     double sum = 0;     for (j = 0; j < n; j++) {      double r = 1;      for (k = 0; k <= i; k++)       r = r * a[j];      sum += r;     }       Sumx[i] = sum;    }    /*     * for(i=0;i<s;i++){ System.out.print(Sumx[i]+"  "); }     */    // System.out.println();    double Sumxy[] = new double[m];    for (i = 0; i < m; i++) {     double sumxy = 0;     for (j = 0; j < n; j++) {      double p = 1;      double w = 0;      for (k = 0; k <= i; k++)       p = p * a[j];      w = p * b[j];      sumxy += w;     }     Sumxy[i] = sumxy;    }    /*     * for(i=0;i<m;i++){ System.out.print(Sumxy[i]+"  "); }     */    // System.out.println();    int t = m + 1;    int q = m + 2;    double A[][] = new double[t][q];    A[0][0] = n;    A[0][q - 1] = sumy;    for (j = 1; j < q - 1; j++)     A[0][j] = Sumx[j - 1];    for (i = 1; i < t; i++)     for (j = 0; j < q - 1; j++)      A[i][j] = Sumx[i + j - 1];    for (i = 1; i < t; i++)     A[i][q - 1] = Sumxy[i - 1];    /*     * for (i = 0; i < t; i++) { int count1 = 0; for (j= 0; j < q;j++) {     * System.out.print(A[i][j] + "  "); count1++; if (count1 == q)     * System.out.println(); } }     */    for (k = 0; k < t; k++) {     for (i = k + 1; i < t; i++) {      double L = A[i][k] / A[k][k];      for (j = 0; j < q; j++)       A[i][j] = A[i][j] - L * A[k][j];     }    }    for (k = t - 1; k >= 0; k--) {     for (i = k - 1; i >= 0; i--) {      double L = A[i][k] / A[k][k];      for (j = q - 1; j >= k; j--)       A[i][j] = A[i][j] - L * A[k][j];     }    } // 求多项式的系数    /*     * for (i = 0; i < t; i++) { int count1 = 0; for (j= 0; j < q;j++) {     * System.out.print(A[i][j] + "  "); count1++; if (count1 == q)     * System.out.println(); } }     */    double r[] = new double[t];    for (i = 0; i < t; i++) {     r[i] = A[i][q - 1] / A[i][i];     // System.out.println("x"+i+"="+r[i]);    }    double x;    System.out.println("输入计算的值");    Scanner sc1 = new Scanner(System.in);    x = sc1.nextDouble();      double SUM = 0;    double Z[] = new double[t];    for (i = 0; i < t; i++) {     double z = 1;     for (j = 1; j <= i; j++)      z = z * x;     Z[i] = z * r[i];      }    for (i = 0; i < t; i++)     SUM += Z[i];    System.out.println("f(" + x + ")" + "=" + SUM);   }  }