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javabigdecimal

Remove trailing numbers

Why I get trailing so many numbers when I run below code?

BigDecimal lat =  new BigDecimal(0.0077);

System.out.println(lat);

output >> 0.00770000000000000024702462297909733024425804615020751953125

I want to print exactly what I entered. How can I do this?

Solution

  • Most finite decimal fractions cannot be exactly represented by floating-point, so that is the approximation you get when you create the floating-point literal 0.0077.

    To avoid the problem, use the constructor BigDecimal(String val) instead: 

    BigDecimal lat = new BigDecimal("0.0077");

    As @TimB points out, if you already have a double value, you can also use: 

    BigDecimal lat = BigDecimal.valueOf(doubleVal);

    Also, here is the mandatory reference to What Every Computer Scientist Should Know About Floating-Point Arithmetic.