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  1. #include <iostream>
  2. #include <cmath>
  3. using namespace std;
  4.  
  5. // Define the function whose root we want to find
  6. double f(double x) {
  7.     return x * x * x + x * x - 1;  // Example: f(x) = x^3 + x^2 - 1
  8. }
  9.  
  10. int main() {
  11.     double x1, x2, x0, f1, f2, f0, E;
  12.     int maxIter, iteration = 1;
  13.  
  14.     // Input initial guesses and tolerance
  15.     cout << "Enter the value of x1: ";
  16.     cin >> x1;
  17.     cout << "Enter the value of x2: ";
  18.     cin >> x2;
  19.     cout << "Enter desired tolerance (E): ";
  20.     cin >> E;
  21.     cout << "Enter maximum number of iterations: ";
  22.     cin >> maxIter;
  23.  
  24.     f1 = f(x1);
  25.     f2 = f(x2);
  26.  
  27.     // Check if initial guesses bracket a root
  28.     if (f1 * f2 > 0) {
  29.         cout << "Incorrect initial guesses. They do not bracket a root.\n";
  30.         return 1;
  31.     }
  32.  
  33.     cout << "Iteration\tx1\t\tx2\t\tx0\t\tf(x0)\n";
  34.     cout << "--------------------------------------------------------------\n";
  35.  
  36.     do {
  37.         x0 = (x1 + x2) / 2;
  38.         f0 = f(x0);
  39.  
  40.         cout << iteration << "\t\t" << x1 << "\t" << x2 << "\t" << x0 << "\t" << f0 << endl;
  41.  
  42.         if (f1 * f0 < 0) {
  43.             x2 = x0;
  44.             f2 = f0;
  45.         } else {
  46.             x1 = x0;
  47.             f1 = f0;
  48.         }
  49.  
  50.         iteration++;
  51.  
  52.         if (fabs((x2 - x1) / x2) < E) break;
  53.  
  54.     } while (iteration <= maxIter);
  55.  
  56.     cout << "\nApproximate root = " << (x1 + x2) / 2 << endl;
  57.  
  58.     return 0;
  59. }
  60.  
Success #stdin #stdout 0.01s 5292KB
comments (?)
stdin 
-1
3
stdout 
Enter the value of x1: Enter the value of x2: Enter desired tolerance (E): Enter maximum number of iterations: Iteration	x1		x2		x0		f(x0)
--------------------------------------------------------------
1		-1	3	1	1

Approximate root = 0
https://ideone.com/C28tLZ
language:
C++ (gcc 8.3)
created:
5 days ago
visibility:
public

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