2011年8月10日 · I often seen the symbol 1L (or 2L, 3L, etc) appear in R code. Whats the difference between 1L and 1? 1==1L evaluates to TRUE. Why is 1L used in R code?

The L specifies that the number is a long type, so -1L is a long set to negative one, and 1L is a long set to positive one. As for why ftell doesn't just return NULL, it's because NULL is used for pointers, and here a long is returned. Note that 0 isn't used because 0 …

The 1L has no special meaning. It is just a number that will match 1L as the "other" version id. To my mind, you are better off either using 0L, or a version number that was (at some point) generated using the standard algorithm. If you use 0L, then you get definite deserialization exceptions if classes change in ways that could be source of ...

2020年12月4日 · (long) 1 evaluates to the same constant as 1L. However in the first case the number (1) is evaluated as integer whereas 1L is always a long. Therefore (long) 123_123_123_123 is invalid since "123_123_123_123" is outside of the integer range, whereas 123_123_123_123L is valid. –

2013年1月1日 · What does "0L", "1L" mean in C ? How is it different from "0" and "1" ? Is there other literals than "L ...

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Possible Duplicate: What is a serialVersionUID and why should I use it? what is meant by that in a servlet (private static final long serialVersionUID = 1L)?

2014年7月31日 · In former example value of expression is 1 as -1L < 1L. In latter case -1L is promoted to unsigned type by repeatedly adding or substracting n+1, when n is the largest value of type unsigned long (in your case n+1 == 2^32), which yields into large number (i.e. 2^32-1), thus value of whole expression is 1 (of type int) as well.

-1L >>> 1 // ? or (int)-1 >>> 1 // ? So even if the number is in the common range, we need to specify type. If the default changed with magnitude of the literal, then there would be a weird change in the interpretations of expressions just from changing the digits.

2017年8月27日 · 1L<<count wouldn't produce valid results beyond the range of unsigned long long. It can produce invalid results, when shifting yields a negative number. If you want results in the range of unsigned long long, use (1ULL << count) instead. –