Basic Knowledge of Computers

This page explains what a computer is.

Definition of a Computer

A computer is a machine that has the following five units:

1. Input unit
2. Output unit
3. Storage unit
4. Control unit
5. Arithmetic logic unit

Roughly speaking, a computer is a machine that performs a specific process on a certain input and outputs the result. It can store, calculate, and output the input data. Control has the role of controlling the aforementioned four units.

What is needed to operate a computer

To operate a computer, programs (software) are needed in addition to the devices (hardware).

Programs instruct the computer on what kind of processing to perform. Programs are written in a format that the computer can understand.

An example of a program is as follows. A program that calculates the sum from 1 to an input integer:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24

#include <iostream>
using namespace std;

int main() {
    // Secure necessary storage area
    int n, sum = 0;
    
    // Output
    cout << "Please enter an integer: ";
    
    // Input 
    cin >> n;
    
    // Calculation
    for (int i = 1; i <= n; i++) { // Calculation
        sum += i;
    }
    
    // Output
    cout << "The sum from 1 to " << n << " is " << sum << "." << endl;
    
    // Exit
    return 0;
}

The program is converted into machine code by a compiler, transforming it into a format that the computer can execute.