Answer 1

basically,Header files contain definitions of Functions and Variables, which is imported or used into any C++ program by using the pre-processor #include statement. Header file have an extension ".h" which contains C++ function declaration and macro definition.
conio.h is system header file which is abbreviated as console input-output.it is part of compiler's runtime library.The library functions declared by conio.h vary somewhat different from compiler to compiler.the combination of display monitor and keyboard (or other device that allows input). Another term for console is terminal. The term console usually refers to a terminal attached to a minicomputer or mainframe and used to monitor the status of the system.