C/C++ IO are based on streams, which are sequence of bytes flowing in and out of the programs (just like water and oil flowing through a pipe). In input operations, data bytes flow from an input source (such as keyboard, file, network or another program) into the program.

In C++, the use of I/O operators aids in taking input and displaying output. Also, the operator used to accept input is known as the extraction or get from operator (>>), whereas the operator used to display output is known as the insertion or put to operator ().