What does C++ standard library contains

Question

While learning c++ i have most of the times used this using namespace std; and know that it means to include features from c++ standard library. but what is c++ standard libraray, what does it contain. plz help with that

Answer 1

alot http://www.cplusplus.com/reference/

Answer 2

The main thing would be cin and cout. This is generally what you would include it for.

It also contains things in these categories:
<array>, <algorithm>, <bitset>, <cassert>, <cctype>, <cerrno>, <cfloat>, <ciso646>, <climits>, <clocale>, <cmath>, <complex>, <csetjmp>, <csignal>, <cstdarg>, <cstddef>, <cstdio>, <cstdlib>, <cstring>, <ctime>, <cwchar>, <cwctype>, <deque>, <exception>, <fstream>, <functional>, <iomanip>, <ios>, <iosfwd>, <iostream>, <istream>, <iterator>, <limits>, <list>, <locale>, <map>, <memory>, <new>, <numeric>, <ostream>, <queue>, <set>, <sstream>, <stack>, <stdexcept>, <streambuf>, <string>, <typeinfo>, <utility>, <valarray>, <vector>