java - 在java中打印大的乘数

Question

这个问题已经有答案了:

Why, In Java arithmetic, overflow or underflow will never throw an Exception? (4 个回答)

已关闭 5 年前。

我正在做 AP Comp Sci 复习表，但编译时我不明白为什么

System.out.println(365 * 24 * 3600 * 1024 * 1024 * 1024);答案是0。我知道int是32位，最大为2147483647，不能给你3386152216166400，但为什么它不会给出溢出异常错误或类似的错误？

Answer 1

来自Java Language Specification ,

The integer operators do not indicate overflow or underflow in any way.

这就是为什么你没有得到任何异常。

结果是specified by the language如下，

If an integer multiplication overflows, then the result is the low-order bits of the mathematical product as represented in some sufficiently large two's-complement format. As a result, if overflow occurs, then the sign of the result may not be the same as the sign of the mathematical product of the two operand values.

Integer.MAX_VALUE + 1 == Integer.MIN_VALUE

Integer.MIN_VALUE - 1 == Integer.MAX_VALUE 

这就是为什么你的结果为零。