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  1. #include <iostream>
  2. #include <cmath>
  3. #include <functional>
  4. #include <iomanip>
  5. using namespace std;
  6.  
  7.  bool correct = false;
  8. double solve(function<double (double)> f, double a, double b, double eps)
  9. {
  10.     if (a > b) swap(a, b);
  11.     while(fabs(a - b) > eps && (correct = f(a)*f(b) < 0)) {
  12.         double x = (a + b) / 2.0;
  13.         if ( f(a) * f(x) < 0 )
  14.             b = x;
  15.         else a = x;
  16.     }
  17.     return (a + b) / 2.0;
  18. }
  19.  
  20. int main()
  21. {
  22.     /*auto f1 = [](double x)->double { return 2 * pow(x, 2.0) - pow(0.5, x) - 3; };*/
  23.     auto f1 = [](double x)->double { return x*x - 0.5; };
  24.     cout <<"[2;3] : "<<fixed << setprecision(11) << solve( f1, 2, 3, 0.001 );
  25.     if(correct)
  26.     cout<<" correct";
  27.     else
  28.     cout<<" incorrect";
  29.     cout <<"[0;1] : "<<fixed << setprecision(11) << solve( f1,0, 1, 0.001 );
  30.     if(correct)
  31.     cout<<" correct";
  32.     else
  33.     cout<<" incorrect";
  34.     cin.get();
  35.     return 0;
  36. }
Success #stdin #stdout 0s 2992KB
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Standard input is empty
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[2;3] : 2.50000000000 incorrect[0;1] : 0.70751953125 correct
https://ideone.com/K4BOAg
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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