Converting large scientific number to long

Question

I've spend a long time now, trying to convert the number 1.2846202978398e+19 in java, without any luck. Currently what I'm trying to do (long)Double.parseDouble(hashes), however this gives 9223372036854775807, which is obviously incorrect. The actual number should look something like this 12855103593745000000.

Using int val = new BigDecimal(stringValue).intValue(); returns -134589568 as it's unable to hold the result. Switching the code to long val = new BigDecimal(hashes).longValue(); gives me -5600541095311551616 which is also incorrect.

I'm assuming this is happening due to the size of a double compared to a long.

Any ideas?

Answer 1

Did you try to use String.format :

String result = String.format("%.0f", Double.parseDouble("1.2846202978398e+19"));
System.out.println(result);

Output

12846202978398000000

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Edit

Why you don't work with BigDecimal to do the arithmetic operations, for example :

String str = "1.2846202978398e+19";
BigDecimal d = new BigDecimal(str).multiply(BigDecimal.TEN);
//                                 ^^^^^^^^------example of arithmetic operations


System.out.println(String.format("%.0f", d));
System.out.println(String.format("%.0f", Double.parseDouble(str)));

Output

128462029783980000000
12846202978398000000