java是否指定了大浮点文本的舍入模式？

Question

考虑下面的代码：

System.out.printf("%f%n", 123456796f);

这会在我的系统上打印123456800，因此该值被四舍五入。在这种情况下，是强制四舍五入，还是编译器也会决定四舍五入，从而产生123456792

Answer 1

Java Language Specification, §3.10.2, Floating-Point Literals

The details of proper input conversion from a Unicode string representation of a floating-point number to the internal IEEE 754 binary floating-point representation are described for the methods valueOf of class Float and class Double of the package java.lang.

^{} Javadoc

s is regarded as representing an exact decimal value in the usual "computerized scientific notation" or as an exact hexadecimal value; this exact numerical value is then conceptually converted to an "infinitely precise" binary value that is then rounded to type float by the usual round-to-nearest rule of IEEE 754 floating-point arithmetic [...]