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  1. #include <iostream>
  2. #include <sstream>
  3. #include <cmath>
  4.  
  5. void quadratic( double a, double b , double c , std::string &x1 , std::string &x2 )
  6. {
  7.     // ( -b +/- sqrt( b*b - ( 4 * a * c ) ) ) / ( 2 * a )
  8.     //if discriminant is negative it is imaginary
  9.     double discriminant = b * b - ( 4 * a * c );
  10.     double denominator = 2 * a;
  11.     bool imaginary = false;
  12.  
  13.     if( discriminant < 0 )
  14.     {
  15.     	imaginary = true;
  16.     	discriminant = -discriminant;
  17.     }
  18.     std::stringstream ss;
  19.     if( imaginary )
  20.     {
  21.     	ss << -b / denominator;
  22.     	x1 = ss.str() + '+';
  23.     	x2 = ss.str() + '-';
  24.     	ss.str("");
  25.     	ss.clear();
  26.     	ss << sqrt( discriminant ) / denominator;
  27.     	x1 += ss.str() + 'i';
  28.     	x2 += ss.str() + 'i';
  29.     }
  30.     else
  31.     {
  32.     	ss << ( -b + sqrt( discriminant ) ) / denominator;
  33.     	x1 = ss.str();
  34.     	ss.str("");
  35.     	ss.clear();
  36.     	ss << ( -b - sqrt( discriminant ) ) / denominator ;
  37.     	x2 = ss.str();
  38.     }
  39. }
  40.  
  41. int main()
  42. {
  43. 	double a = 1.0;
  44. 	double b = -11.0;
  45. 	double c = 36.5;
  46.  
  47. 	std::string x1 = "";
  48. 	std::string x2 = "";
  49.  
  50. 	quadratic( a , b , c , x1 , x2 );
  51.  
  52. 	std::cout << x1 << std::endl;
  53. 	std::cout << x2 << std::endl;
  54.  
  55. 	quadratic( -1 , 10 , 5 , x1 , x2 );
  56.  
  57. 	std::cout << x1 << std::endl;
  58. 	std::cout << x2 << std::endl;
  59. 	return(0);
  60. }
Success #stdin #stdout 0s 3480KB
comments (?)
stdin 
Standard input is empty
stdout 
5.5+2.5i
5.5-2.5i
-0.477226
10.4772
https://ideone.com/YegMWE
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
public

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