cppreference.com > C++ String Streams > Operators String Stream Operators Syntax:
      #include <sstream>
      operator<<
      operator>>
Like C++ I/O Streams, the simplest way to use string streams is to take advantage of the overloaded << and >> operators. The << operator inserts data into the stream. For example:
      stream1 << "hello" << i;
This example inserts the string "hello" and the variable i into stream1. In contrast, the >> operator extracts data out of a string stream:
      stream1 >> i;
This code reads a value from stream1 and assigns the variable i that value. Related topics: C++ I/O Streams