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  1. #include <iostream>
  2. #include <complex>
  3.  
  4. void print(const std::complex<double> (&matrix)[2][2])
  5. {
  6. 	for(const auto& row: matrix) {
  7. 		for(const auto& c: row)
  8. 			std::cout << c << ' ';
  9. 		std::cout << '\n';
  10. 	}
  11. }
  12.  
  13. void multiply(std::complex<double> (&lhs)[2][2], const std::complex<double> (&rhs)[2][2])
  14. {
  15.     std::complex<double> result[2][2];
  16.     for(int i = 0; i < 2; ++i) for(int j = 0; j < 2; ++j)
  17.     	result[i][j] = lhs[i][0]*rhs[0][j] + lhs[i][1]*rhs[1][j];
  18.     for(int i = 0; i < 2; ++i) for(int j = 0; j < 2; ++j)
  19.         lhs[i][j] = result[i][j];
  20. }
  21.  
  22. void power(std::complex<double> (&matrix)[2][2], unsigned n)
  23. {
  24.     std::complex<double> result[2][2] = {{1, 0}, {0, 1}};
  25.     for(int i = 0; i < n; ++i)
  26.         multiply(result, matrix);
  27.     for(int i = 0; i < 2; ++i) for(int j = 0; j < 2; ++j)
  28.         matrix[i][j] = result[i][j];
  29. }
  30.  
  31. int main() 
  32. {
  33. 	using namespace std::complex_literals;
  34. 	std::complex<double> matrix[2][2] = 
  35. 	    {{ 1.0 + 0i, 0.0 + 1i}, 
  36. 	     {-1.0 + 0i, 0.0 - 1i}};
  37. 	print(matrix);
  38. 	std::cout << '\n';
  39. 	power(matrix, 1);
  40. 	print(matrix);
  41. 	std::cout << '\n';
  42. 	power(matrix, 2);
  43. 	print(matrix);
  44. 	std::cout << '\n';
  45. }
Success #stdin #stdout 0s 3272KB
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stdin
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Standard input is empty
stdout
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(1,0) (0,1) 
(-1,0) (0,-1) 

(1,0) (0,1) 
(-1,0) (0,-1) 

(1,-1) (1,1) 
(-1,1) (-1,-1)
https://ideone.com/FcSvhf
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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