There are many functions in C++ programming language that are built in and are defined by C++ standard library. Some of these functions are; getche (), cout, cin, getch (), etc.
These functions are used by including their header files in the program. And all are defined by the standard C++ library.
All data types, mathematic function, strings, file input/output, memory allocation, date and time, signals and input and output functions are defined in the standard library.
The header file for input/output function is <iostream.h> in console application and <iostream> in visual C++. In visual C++ when using iostream, we use “using namespace std” also.