Java Floating point number (note)

1. In the computer, the floating-point number is different from the decimal number.

 Public Static void Main (string[] args) {        double B1 = 0.1;         double b2 = 0.2;         double result = B1 + B2;        System.out.print (result);    }

Results: 0.30000000000000004

Cause: The computer uses the binary to store the data.

PS. Use floating-point numbers to make conditional judgments. For example (while (f! = 0.3) can always loop).

　　

2. Large numbers plus decimals in floating-point numbers

 Public Static void Main (string[] args) {        float f1 = 30000000;         float F2 = 1;         float r = f1 + F2;         if (R < F1)            System.out.println ("left smaller");         Else             System.out.println ("What?") );    }

Result: What?

Cause: The larger the floating-point number, the greater the gap between the two adjacent floating-point numbers.

3. Floating-point numbers to other types

 Public Static void Main (string[] args) {        System.out.println ((int) double.nan);        System.out.println ((int) double.positive_infinity);        System.out.println ((int) double.negative_infinity);    }

Results: 0

2147483647
-2147483648

　　　　　

　　

Java Floating point number (note)