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  1. /* package whatever; // don't place package name! */
  2.  
  3. import java.util.*;
  4. import java.lang.*;
  5. import java.io.*;
  6.  
  7. /* Name of the class has to be "Main" only if the class is public. */
  8. class Ideone
  9. {
  10. 	/**
  11. 	 * Round half away from zero ('commercial' rounding)
  12. 	 * Uses correction to offset floating-point inaccuracies.
  13. 	 * Works symmetrically for positive and negative numbers.
  14. 	 */
  15. 	public static double round(double num, int digits) {
  16.  
  17. 	    // epsilon correction
  18. 	    double n = Double.longBitsToDouble(Double.doubleToLongBits(num) + 1);
  19. 	    double p = Math.pow(10, digits);
  20. 	    return Math.round(n * p) / p;
  21. 	}
  22.  
  23. 	public static void main (String[] args) throws java.lang.Exception
  24. 	{
  25. 		// test rounding of half
  26. 		System.out.println(round(0.5, 0));   // 1
  27. 		System.out.println(round(-0.5, 0));  // -1
  28.  
  29. 		// testing edge cases
  30. 		System.out.println(round(1.005, 2));   // 1.01
  31. 		System.out.println(round(2.175, 2));   // 2.18
  32. 		System.out.println(round(5.015, 2));   // 5.02
  33.  
  34. 		System.out.println(round(-1.005, 2));  // -1.01
  35. 		System.out.println(round(-2.175, 2));  // -2.18
  36. 		System.out.println(round(-5.015, 2));  // -5.02
  37. 	}
  38. }
  39.  
Success #stdin #stdout 0.06s 33080KB
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stdin
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Standard input is empty
stdout
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1.0
-1.0
1.01
2.18
5.02
-1.01
-2.18
-5.02
https://ideone.com/TnTOic
language:
Java (HotSpot 12)
created:
3 years ago
visibility:
public

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