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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. double f(double x)
  5. {
  6.     return 2 * x * x * x + 3 * x - 1;
  7. }
  8.  
  9. int main() 
  10. {
  11.     double x1, x2, x0, f1, f2, f0;
  12.     double E = 1e-8;
  13.  
  14.     cout << "Enter the value of x0: ";
  15.     cin >> x1;
  16.     cout << "\nEnter the value of x1: ";
  17.     cin >> x2;
  18.  
  19.     f1 = f(x1);
  20.     f2 = f(x2);
  21.  
  22.     if (f1 * f2 > 0)
  23.     {
  24.         cout << "\nInvalid interval.\n";
  25.         return 0;
  26.     }
  27.  
  28.     cout << "\nIteration\t x0\t\t x1\t\t x2\t\t f0\t\t f1\t\t f2\n";
  29.  
  30.     for (int i = 1; ; i++)
  31.     {
  32.         x0 = (x1 + x2) / 2;
  33.         f0 = f(x0);
  34.  
  35.         cout << fixed << setprecision(6);
  36.         cout << setw(3) << i << "\t" << x0 << "\t" << x1 << "\t" << x2
  37.              << "\t" << f0 << "\t" << f1 << "\t" << f2 << endl;
  38.  
  39.         if (fabs((x2 - x1) / x2) < E)
  40.         {
  41.             cout << "\nApproximate root = " << x0 << endl;
  42.             break;
  43.         }
  44.  
  45.         if (f1 * f0 < 0)
  46.             x2 = x0, f2 = f0;
  47.         else
  48.             x1 = x0, f1 = f0;
  49.     }
  50.  
  51.     return 0;
  52. }
  53.  
Success #stdin #stdout 0s 5308KB
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stdin
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4 
-2
stdout
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Enter the value of x0: 
Enter the value of x1: 
Iteration	 x0		 x1		 x2		 f0		 f1		 f2
  1	1.000000	4.000000	-2.000000	4.000000	139.000000	-23.000000
  2	-0.500000	1.000000	-2.000000	-2.750000	4.000000	-23.000000
  3	0.250000	1.000000	-0.500000	-0.218750	4.000000	-2.750000
  4	0.625000	1.000000	0.250000	1.363281	4.000000	-0.218750
  5	0.437500	0.625000	0.250000	0.479980	1.363281	-0.218750
  6	0.343750	0.437500	0.250000	0.112488	0.479980	-0.218750
  7	0.296875	0.343750	0.250000	-0.057045	0.112488	-0.218750
  8	0.320312	0.343750	0.296875	0.026666	0.112488	-0.057045
  9	0.308594	0.320312	0.296875	-0.015444	0.026666	-0.057045
 10	0.314453	0.320312	0.308594	0.005546	0.026666	-0.015444
 11	0.311523	0.314453	0.308594	-0.004965	0.005546	-0.015444
 12	0.312988	0.314453	0.311523	0.000287	0.005546	-0.004965
 13	0.312256	0.312988	0.311523	-0.002340	0.000287	-0.004965
 14	0.312622	0.312988	0.312256	-0.001027	0.000287	-0.002340
 15	0.312805	0.312988	0.312622	-0.000370	0.000287	-0.001027
 16	0.312897	0.312988	0.312805	-0.000042	0.000287	-0.000370
 17	0.312943	0.312988	0.312897	0.000122	0.000287	-0.000042
 18	0.312920	0.312943	0.312897	0.000040	0.000122	-0.000042
 19	0.312908	0.312920	0.312897	-0.000001	0.000040	-0.000042
 20	0.312914	0.312920	0.312908	0.000020	0.000040	-0.000001
 21	0.312911	0.312914	0.312908	0.000009	0.000020	-0.000001
 22	0.312910	0.312911	0.312908	0.000004	0.000009	-0.000001
 23	0.312909	0.312910	0.312908	0.000002	0.000004	-0.000001
 24	0.312909	0.312909	0.312908	0.000000	0.000002	-0.000001
 25	0.312908	0.312909	0.312908	-0.000000	0.000000	-0.000001
 26	0.312908	0.312909	0.312908	0.000000	0.000000	-0.000000
 27	0.312908	0.312908	0.312908	-0.000000	0.000000	-0.000000
 28	0.312908	0.312908	0.312908	0.000000	0.000000	-0.000000
 29	0.312908	0.312908	0.312908	-0.000000	0.000000	-0.000000
 30	0.312908	0.312908	0.312908	0.000000	0.000000	-0.000000
 31	0.312908	0.312908	0.312908	0.000000	0.000000	-0.000000
 32	0.312908	0.312908	0.312908	-0.000000	0.000000	-0.000000

Approximate root = 0.312908
https://ideone.com/4ACEG2
language:
C++ (gcc 8.3)
created:
11 days ago
visibility:
public

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