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  1. #include <iostream>       //id=240242103
  2. #include <cmath>
  3. #include <iomanip>
  4. using namespace std;
  5.  
  6. double horner(double coeff[], int n, double x) {
  7.     double result = coeff[n];
  8.     for (int i = n - 1; i >= 0; i--)
  9.         result = result * x + coeff[i];
  10.     return result;
  11. }
  12.  
  13. double horner_derivative(double coeff[], int n, double x) {
  14.     double result = n * coeff[n];
  15.     for (int i = n - 1; i >= 1; i--)
  16.         result = result * x + i * coeff[i];
  17.     return result;
  18. }
  19.  
  20. int main() {
  21.     int degree;
  22.     cout << "ENTER THE TOTAL NO. OF POWER:::: ";
  23.     cin >> degree;
  24.  
  25.     double coeff[degree + 1];
  26.     for (int i = 0; i <= degree; i++) {
  27.         cout << "x^" << i << "::";
  28.         cin >> coeff[i];
  29.     }
  30.  
  31.     cout << "THE POLYNOMIAL IS ::: ";
  32.     for (int i = degree; i >= 0; i--) {
  33.         if (coeff[i] >= 0 && i != degree) cout << "+";
  34.         cout << coeff[i] << "x^" << i << " ";
  35.     }
  36.     cout << endl;
  37.  
  38.     double x0;
  39.     cout << "INITIAL X1 ------ >";
  40.     cin >> x0;
  41.  
  42.     double E = 1e-6; // stopping criterion
  43.     double x1, f0, f1, Ea;
  44.     int iter = 0;
  45.  
  46.     cout << "**************************************\n";
  47.     cout << "ITERATION  X      FX      F'X      Ea(%)\n";
  48.     cout << "**************************************\n";
  49.  
  50.     do {
  51.         f0 = horner(coeff, degree, x0);
  52.         f1 = horner_derivative(coeff, degree, x0);
  53.         x1 = x0 - f0 / f1;
  54.  
  55.         if (iter == 0)
  56.             Ea = 0;
  57.         else
  58.             Ea = fabs((x1 - x0) / x1) * 100;
  59.  
  60.         iter++;
  61.         cout << iter << "\t" << x1 << "\t" << f0 << "\t" << f1 << "\t" << Ea << endl;
  62.  
  63.         x0 = x1;
  64.  
  65.     } while (Ea > E);
  66.  
  67.     cout << "**************************************\n";
  68.     cout << "THE ROOT OF EQUATION IS " << fixed << setprecision(6) << x1 << endl;
  69.  
  70.     return 0;
  71. }
  72.  
Success #stdin #stdout 0.01s 5300KB
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stdin
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stdout
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ENTER THE TOTAL NO. OF POWER:::: x^0::x^1::x^2::x^3::THE POLYNOMIAL IS ::: 1x^3 +0x^2 -1x^1 -3x^0 
INITIAL X1 ------ >**************************************
ITERATION  X      FX      F'X      Ea(%)
**************************************
1	2.19231	21	26	0
**************************************
THE ROOT OF EQUATION IS 2.192308
https://ideone.com/K7qwfE
language:
C++ (gcc 8.3)
created:
6 days ago
visibility:
public

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