C++ vector max_size();

On 32 bit System.

1. std::vector<char>::max_size() returns 2³²-1, size of char — 1 byte
2. std::vector<int>::max_size() returns 2³⁰-1, size of int — 4 byte
3. std::vector<double>::max_size() returns 2²⁹-1, size of double — 8 byte

can 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.

Simply get the answer by

std::vector<dataType> v;
std::cout << v.max_size();

Or we can get the answer by (2^nativePointerBitWidth)/sizeof(dataType) - 1. For example, on a 64 bit system, long long is (typically) 8 bytes wide, so we have (2^64)/8 - 1 == 2305843009213693951.