what is the usage of getch() function?
how to creat recovery softwear?

getch() is a predefined function that is used with the header file #include<conio.h> where conio stands for console input and output.This can be used both in c and c++.
Using getch which consists of two words get,ch that is get the character.It is always used at the end of the program,that is used to hold the screen in simple language.,without using this the screen will just flash and goes away.[if we use this the screen will remain with an symbol(-) saying thatit waits to get a char.]Hope you understand.please be clear with the second question.

how to creat recovery softwear?

Study c or c++ for a couple years and you might be ready to answer that question yourself.