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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. double f(double x) 
  4. {
  5.     double coe[] = {1, 0, -4, -9};
  6.     double result = coe[0];
  7.     for (int i = 1; i < 4; i++)
  8.         result = result * x + coe[i];
  9.     return result;
  10. }
  11.  
  12. int main()
  13. {
  14.     double x1, x2;
  15.     cout << "Enter the value of x1: ";
  16.     cin >> x1;
  17.     cout << "\nEnter the value of x2: ";
  18.     cin >> x2;
  19.  
  20.     cout << "\n\n";
  21.     cout << "   Iteration" << setw(10) << "x1" << setw(12) << "x2"
  22.          << setw(12) << "x3" << setw(12) << "f(x1)" << setw(12) << "f(x2)" << endl;
  23.     cout << "   --------------------------------------------------------------------------\n";
  24.  
  25.     double f1 = f(x1);
  26.     double f2 = f(x2);
  27.     double x3, f3;
  28.     int step = 1;
  29.  
  30.     do {
  31.         x3 = (f2 * x1 - f1 * x2) / (f2 - f1);
  32.         f3 = f(x3);
  33.  
  34.         cout << setw(8) << step
  35.              << setw(14) << fixed << setprecision(6) << x1   << setw(12) << x2 << setw(12) << x3
  36.              << setw(12) << f1  << setw(12) << f2 << endl;
  37.  
  38.         if (fabs(f3) < 0.00001)
  39.             break;
  40.  
  41.         x1 = x2;
  42.         f1 = f2;
  43.         x2 = x3;
  44.         f2 = f3;
  45.         step++;
  46.     } while (step <= 8);
  47.  
  48.     cout << "   --------------------------------------------------------------------------\n";
  49.     cout << "\n   Approximate root = " << fixed << setprecision(6) << x3 << endl;
  50.     cout << endl;
  51.  
  52.     return 0;
  53. }
  54.  
Success #stdin #stdout 0.01s 5280KB
comments (?)
stdin 
4
2
stdout 
Enter the value of x1: 
Enter the value of x2: 

   Iteration        x1          x2          x3       f(x1)       f(x2)
   --------------------------------------------------------------------------
       1      4.000000    2.000000    2.375000   39.000000   -9.000000
       2      2.000000    2.375000    2.866165   -9.000000   -5.103516
       3      2.375000    2.866165    2.681284   -5.103516    3.080613
       4      2.866165    2.681284    2.704785    3.080613   -0.448618
       5      2.681284    2.704785    2.706548   -0.448618   -0.031298
       6      2.704785    2.706548    2.706528   -0.031298    0.000360
   --------------------------------------------------------------------------

   Approximate root = 2.706528
https://ideone.com/rOBI28
language:
C++ (gcc 8.3)
created:
15 days ago
visibility:
public

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