尤达条件和整数提升
当将大于 int 的类型与整数常量进行比较时，我应该将常量放在左侧还是右侧以确保执行正确的比较？
int64_t i = some_val;
if (i == -1)
或者应该是：
if (-1 == i)
是否存在任何情况与 -1LL 的比较不同（其中 int64_t 是 long long）？
When comparing a type larger than int, with an integer constant, should I place the constant on the left or the right to ensure the correct comparison is performed?
int64_t i = some_val;
if (i == -1)
or should it be:
if (-1 == i)
Are there any circumstances in which either case is not identical to comparison with -1LL (where int64_t is long long)?
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无论您将其放在右侧还是左侧，都没有关系；
==运算符是完全对称的。如果
==运算符的两个操作数都具有算术类型（如本例所示），则应用“常规算术转换”（C99 §6.5.9）。在这种情况下，适用的规则是：因此 -1 被转换为
int64_t。-1LL没有区别。It doesn't matter whether you put it on the right hand side or the left hand side; the
==operator is completely symmetrical.If both operands to the
==operator have arithmetic type, as in this case, then the "usual arithmetic conversions" are applied (C99 §6.5.9). In this case, the rule that applies is:So the -1 is converted to
int64_t.-1LLmakes no difference.