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  1. #include <iostream>
  2. #include <iomanip>
  3. #include <sstream>
  4. #include <cmath>
  5.  
  6. size_t digits_before_point(double x)
  7. {
  8. 	return x ? size_t(std::max(0.0, floor(std::log(std::abs(x)) / std::log(10.0) + 1))) : 0;
  9. }
  10.  
  11. std::string format(double x, size_t precision = 2)
  12. {
  13. 	std::ostringstream output;
  14. 	output << std::setprecision(digits_before_point(x) + precision) << x;
  15. 	return output.str();
  16. }
  17.  
  18. int main()
  19. {
  20. 	std::cout << format(-123456.949) << std::endl;
  21. 	std::cout << format(-123456.004) << std::endl;
  22. 	std::cout << format(-123456.005) << std::endl;
  23. 	std::cout << format(-123456.) << std::endl;
  24. 	std::cout << format(0) << std::endl;
  25. 	std::cout << format(0.9499) << std::endl;
  26. }
Success #stdin #stdout 0s 4368KB
comments (?)
stdin
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Standard input is empty
stdout
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-123456.95
-123456
-123456.01
-123456
0
0.95
https://ideone.com/uxF948
language:
C++ (gcc 8.3)
created:
4 years ago
visibility:
public

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