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  1. #include <iostream>
  2. #include <iomanip>
  3.  
  4. using namespace std;
  5.  
  6.  
  7.  
  8. double chord(double a, double b, double e, double (*f)(double))
  9. {  // метод хорд
  10.  
  11.     double fa = f(a), fb = f(b);
  12.     if (fa*fb > 0) throw runtime_error("Wrong data");
  13.  
  14.     for(;abs(b-a) > e;)
  15.     {
  16.         double x = a - (b-a)*fa/(fb-fa);
  17.         b = a;
  18.         fb = fa;
  19.         a = x;
  20.         fa = f(x);
  21.     }
  22.     return a;
  23. }
  24.  
  25. double dichotomy(double a, double b, double e, double (*f)(double))
  26. { //метод дихотомии
  27.     double fa = f(a), fb = f(b);
  28.     if (fa*fb > 0) throw runtime_error("Wrong data");
  29.  
  30.     for(;abs(b - a) > e;)
  31.     {
  32.         double x = (a + b)/2;
  33.         if (f(x)*fa > 0)  a = x;
  34.         else              b = x;
  35.     }
  36.     return (a+b)/2;
  37. }
  38.  
  39. double g(double x)
  40. {
  41.     return x * x * x - 18 * x - 83;
  42. }
  43.  
  44. double f(double x)
  45. {
  46.     return x * x * x + 4 * x - 3;
  47. }
  48.  
  49. int main()
  50. {
  51.     try {
  52.         cout << chord(0,1,0.0001,f)  << "  vs  " << dichotomy(0,1,0.0001,f)  << "\n";
  53.         cout << chord(2,10,0.0001,g) << "  vs  " << dichotomy(2,10,0.0001,g) << "\n";
  54.     } catch(exception&e)
  55.     {
  56.         cerr << e.what() << endl;
  57.     }
  58. }
  59.  
Success #stdin #stdout 0s 5520KB
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0.673593  vs  0.673615
5.70512  vs  5.70511
https://ideone.com/8H2Fqq
language:
C++14 (gcc 8.3)
created:
2 years ago
visibility:
public

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