在 C++ 中，避免整数溢出将无符号 int 转换为 int 的有效方法是什么？
以下是在 C++ 中将 unsigned int 转换为 int 的有效且无问题的方法：
#include <limits.h>
void safeConvert(unsigned int passed)
{
int variable = static_cast<int>(passed % (INT_MAX+1));
...
}
还是有更好的方法？
更新
正如 James McNellis 所指出的，分配一个 unsigned int > 并不是未定义的。 INT_MAX 为整数 - 相反，这是实现定义的。因此，这里的上下文现在特别适合我的偏好，以确保当无符号 int 超过 INT_MAX 时该整数重置为零。
原始上下文
我有许多用作计数器的无符号 int，但希望在特定情况下将它们作为整数传递。
在正常操作下，这些计数将保持在 INT_MAX 范围内。但是，为了避免在发生异常（但有效）情况时遇到 undefined 实现特定行为，我希望在这里进行一些有效的转换。
Is the following an efficient and problem free way to convert an unsigned int to an int in C++:
#include <limits.h>
void safeConvert(unsigned int passed)
{
int variable = static_cast<int>(passed % (INT_MAX+1));
...
}
Or is there a better way?
UPDATE
As pointed out by James McNellis it is not undefined to assign an unsigned int > INT_MAX to an integer - rather this is implementation defined. As such the context here is now specifically on my preference is to ensure this integer resets to zero when the unsigned int exceeds INT_MAX.
Original Context
I have a number of unsigned int's used as counters, but want to pass them around as integers in a specific case.
Under normal operation these counts will remain within the bounds of INT_MAX. However to avoid running into undefined implementation specific behaviour should the abnormal (but valid) case occur I want some efficient conversion here.
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评论（2）
这也应该有效：
This should also work:
高效转化为什么？如果 int 和 unsigned int 的所有共享值都对应，并且您希望其他无符号值（例如 INT_MAX + 1）各自具有不同的值，那么您只能将它们映射到负整数值。这是默认完成的，并且可以使用
static_cast(my_unsigned) 显式请求。否则，您可以将它们全部映射为 0、-1、INT_MIN，或者丢弃高位...最简单的方法很简单：if (my_unsigned > INT_MAX) my_unsigned = XXX，或...my_unsigned &= INT_MAX清除高位。但是如果int溢出，被调用的函数还能正常工作吗？也许更好的解决方案是首先使用 64 位整数？Efficient conversion to what? If all the shared values for int and unsigned int correspond, and you want other unsigned values such as INT_MAX + 1 to each have distinct values, then you can only map them onto the negative integer values. This is done by default, and can be explicitly requested with
static_cast<int>(my_unsigned). Otherwise, you could map them all to 0, or -1, or INT_MIN, or throw away the high bit... easiest way is simply:if (my_unsigned > INT_MAX) my_unsigned = XXX, or...my_unsigned &= INT_MAXto clear the high bit. But will the called functions work properly if theintoverflows? Perhaps a better solution would be to use 64-bit ints to begin with?