问题
Is there a more frequent error that is memory-related that throws bad_alloc? I understand that it means that memory-allocation has failed, but what is the most common mistake that leads to this in code?
回答1:
EDIT: The other commenters have pointed out a few interesting scenarios. I'm adding them to my response for the sake of completeness.
Case 1: Running out of memory
My understanding is that bad_alloc is thrown whenever the operators new and new[] fail to allocate memory to an object or variable. This can happen if you've newed a bunch of objects and forgot to delete them before they got out of scope (i.e., your code leaks like crazy).
Case 2: Allocating huge amounts of memory in one swoop
Allocating a large chunk of memory, as in the case of a 1000 x 1000 x 1000 matrix of doubles, will possibly fail because it requires a single block of that size.There might be several free memory blocks available, but none of these are large enough.
Case 3: Passing an invalid value to new[]
bad_alloc is thrown if you pass a negative value as its parameter.
来源：https://stackoverflow.com/questions/50827678/what-is-the-most-common-reason-that-bad-alloc-is-thrown