Computer:- Computer is an electronic device which takes data, process it according to given instructions and gives results. These results are always correct, provided the given data and reproduce them whenever needed. 

Computers performs five basic operations:- 

1.)Inputting:- Inputting is the process of entering data and instruction into the computer system. You can enter data and instruction using any input device. Most popular input device is keyboard.

2.)storing:- Storing is a process of saving data and instruction so that they are available initial and additional processing, as and when required. No instruction can be processed if there is no memory for processing.

3.)Processing:- Processing means performing mathematical or logical operations on data, in order to convert them into useful information. Processing is not done automatically, it requires some sort of instruction provided in the form of a language.

4.)Outputting:- Outputting is a process of producing useful information or results to the user, in the form of a printed report or a visual display. Outputting is very important, as  a software that does not yields desired output is useless. Output can be printed form known as permanent or hard copy output or it can just be seen on the monitor, mostly referred as soft copy.

5.)Controlling:- Controlling is a process of directing the manner and sequence in which all the above operation(inputting, storing, processing and outputting) are performed. control is most important section and only proper control yield better and meaningful results.

Components of computer:- Since every task performed on computer use input-process-output cycle. So there must be a device with the help of which we can input data to the computer, there must be a device with which it can input data and there must be a device with which it can display or print the results.

The computer as a system is called IPO(Input processing output) cycle.

The computer system consist of following parts:-

1.)Input Unit:- Input unit is a unit through which user communicates with the computer. It act as a translator between the user and computer. It converts the given data into a computer acceptable form. In brief, input device can be defined as a device which performs the following functions.

2.)Central processing Unit(CPU):- All processing work of computer is performed by CPU(Central processing unit). CPU is also termed as brain of the computer. It controls all the part of computer system. It can be further classified into three components which are responsible for performing different function of CPU. These components are:-

a.)ALU(Arithmetic and logic Unit)

b.)CU(Control Unit)

c.)Memory(or Central Memory

3.)Output Unit:- Output unit is a unit through which computer communicates with user. It acts as a translator between the computer and the user. It converts the processed data from machine language to language like English, which user can understand very easily.