On 32 bit System.
std::vector<char>::max_size()
returns 232-1, size of char
— 1 bytestd::vector<int>::max_size()
returns 230-1, size of int
— 4 bytestd::vector<double>::max_size()
returns 229-1, size of double
— 8 bytecan anyone tell me max_size()
depends on what?
and what will be the return value of max_size()
if it runs on 64 bit system.
max_size()
is the theoretical maximum number of items that could be put in your vector. On a 32-bit system, you could in theory allocate 4Gb == 2^32 which is 2^32 char
values, 2^30 int
values or 2^29 double
values. It would appear that your implementation is using that value, but subtracting 1.
Of course, you could never really allocate a vector that big on a 32-bit system; you'll run out of memory long before then.
There is no requirement on what value max_size()
returns other than that you cannot allocate a vector bigger than that. On a 64-bit system it might return 2^64-1 for char
, or it might return a smaller value because the system only has a limited memory space. 64-bit PCs are often limited to a 48-bit address space anyway.