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  1. #include <iostream>
  2. #include <vector>
  3. #include <cstddef>
  4. #include <cmath>
  5.  
  6.  
  7. auto const pi = std::acos(-1.f);
  8.  
  9. struct sin_table {
  10.  
  11.    explicit sin_table(float const step) : step(step) {
  12.       auto const size = static_cast<std::size_t>(2 * pi / step);
  13.  
  14.       table.resize(size);
  15.  
  16.       for (std::size_t i = 0; i != size; ++i) {
  17.          table[i] = std::sin(i * step);
  18.       }
  19.    }
  20.  
  21.    float operator ()(float const arg) const {
  22.   	  auto const pos = static_cast<std::size_t>(std::abs(arg / step)) % table.size();
  23.    	  auto const value = table[pos];
  24.    	  return std::signbit(arg) ? -value : value;
  25.    }
  26.  
  27. private:
  28.    float const step;
  29.    std::vector<float> table;
  30. };
  31.  
  32.  
  33. int main() {
  34.    sin_table const sin(.01f);
  35.  
  36.    std::cout << sin(.0f) 			<< std::endl;
  37.    std::cout << sin(pi / 2)	        << std::endl;
  38.    std::cout << sin(pi)  			<< std::endl;
  39.    std::cout << sin(3 * pi / 2)     << std::endl;
  40.    std::cout << sin(5 * pi / 2)     << std::endl;
  41.    std::cout << sin(-pi / 2)        << std::endl;
  42.    std::cout << sin(-3 * pi / 2)    << std::endl;
  43.    std::cout << sin(-5 * pi / 2)    << std::endl;
  44. }
  45.  
Success #stdin #stdout 0s 3428KB
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Standard input is empty
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0
1
0.00159279
-0.999997
1
-1
0.999997
-1
https://ideone.com/DqytmG
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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