Java: Preface
Computer Basics
The composition of the computer
The computer system is composed of two parts: hardware system and software system.
Computer hardware
Input and output equipment, memory, controller, arithmetic unit
computer software
Divided into system software and application software
system software
System software: operating system (windows, linux, OS), language processing program, database management system, etc.
application
Application software: library, software package, etc.
The essence of development
I understand that development is to write software to solve the things people encounter in life and make people's lives easier.
What is that software?
Software ( Software ): is a collection of computer data and instructions in accordance with a particular order organizations
The downloaded software is static and stored on the hard disk.
If you start a software, a program will be generated in the memory, which is dynamic.
What are the instructions?
Instructions ( computer instruction ): Computer instructions are instructions and commands that direct the work of a machine, and a program is a series of instructions arranged in a certain order.
The languages that computers can recognize are programming languages
C/C++, PHP, Python, Java, Go, etc.
user-interface:
The interactive interface is a channel for information exchange between humans and computers. The user inputs information and performs operations to the computer through the interactive interface, and the computer provides information to the user through the interactive interface for reading, analysis and judgment.
Graphical interactive interface
Advantages: friendly, beautiful and beautiful interface.
Disadvantages: a certain degree of waste of computer performance
DOS console interactive interface
How to open DOS console
- Windows key+R-->enter cmd-->Enter to enter the DOS interface
- Find the resource file you want to enter cmd, and then enter cmd in the current address bar
1. Enter the cmd command
2. Press Enter -> execute the command
Commonly used DOS commands
| command | Explanation |
|---|---|
| C: or D: | Switch drive letter command |
| to you | Display all files and directories under the current file |
| cd path | Jump to the specified path |
| cd… | Jump to the upper directory |
| md directory name | Create a directory with the specified name |
| rd directory name | Delete the directory with the specified name |
| rd/s directory name | Delete a non-empty directory with the specified name |
| del file name | Delete specified file |
| cls | Clear screen command |
| ipconfig | Check the computer's IP |
| ping command | You can use the ping command to get the IP address of the website you want (ping www.taobao.com) |