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  1. #include <iostream>
  2. #include <iomanip>
  3. #include <cmath>
  4. using namespace std;
  5.  
  6. // Function definition
  7. double f(double x) {
  8.     return 2 * x * x * x + 3 * x - 1;
  9. }
  10.  
  11. int main() {
  12.     double x1, x2, x0, f1, f2, f0;
  13.     double E = 1e-8;
  14.     int i = 0;
  15.  
  16.     cout << "Enter the value of x0: ";
  17.     cin >> x1;
  18.     cout << "\nEnter the value of x1: ";
  19.     cin >> x2;
  20.  
  21.     f1 = f(x1);
  22.     f2 = f(x2);
  23.  
  24.     if (f1 * f2 > 0) {
  25.         cout << "\nInvalid interval. f(x0) and f(x1) must have opposite signs.\n";
  26.         return 0;
  27.     }
  28.  
  29.     cout << "\n-------------------------------------------------------------";
  30.     cout << "\nIteration\t x0\t\t x1\t\t x2\t\t f0\t\t f1\t\t f2";
  31.     cout << "\n-------------------------------------------------------------\n";
  32.  
  33.     do {
  34.         i++;
  35.         x0 = (x1 + x2) / 2;
  36.         f0 = f(x0);
  37.  
  38.         cout << fixed << setprecision(6);
  39.         cout << setw(3) << i << "\t\t"
  40.              << x0 << "\t" << x1 << "\t" << x2 << "\t"
  41.              << f0 << "\t" << f1 << "\t" << f2 << endl;
  42.  
  43.         if (f1 * f0 < 0) {
  44.             x2 = x0;
  45.             f2 = f0;
  46.         } else {
  47.             x1 = x0;
  48.             f1 = f0;
  49.         }
  50.  
  51.     } while (fabs((x2 - x1) / x2) > E);
  52.  
  53.     cout << "\nApproximate root = " << x0 << endl;
  54.  
  55.     return 0;
  56. }
  57.  
Success #stdin #stdout 0s 5316KB
comments (?)
stdin 
4 
-2
stdout 
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

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

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