Von Neumann architecture
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computer software
Computer software is divided into system software and application software according to its functions.
system software
如 Windows，Linux，Mac，Unix，Android，iOS
application
QQ, WeChat, various games, WPS, etc.
Commonly used shortcut keys
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Ctrl +c select copy
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Ctrl+v Paste
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Ctrl +A Select all
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Ctrl+x cut
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Ctrl+z Undo
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Ctrl +s save
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Alt+f4 close window
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shift +delete permanently delete
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Windows +r opens a command line window
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Ctrl +shift +esc open task manager
Basic DOS commands
- Windows+R Open cmd command prompt
# 盘符切换 E :(英文的冒号)
# dir 查找盘下目录
# 切换目录 cd E
#回到主目录 cd..
# 进入目录 cd+进入目录的名字（可使用首字母+tab键）
# 清理屏幕 cls （clean screen）
# 退出终端 exit
# 查看电脑IP ipconfig
# 创建文件 md +名字
# 删除 del
# 删除文件夹 rd
high level language
It can be roughly divided into two categories, process-oriented and object-oriented.
C language is a typical process-oriented language, while C++ and Java are object-oriented languages.
Java
simplicity
Object-oriented (everything is an object) simulates human thinking
Portability (cross-platform) write once, run anywhere because of jvm (virtual machine)
High performance (efficiency is basically close to c++)
Distributed (processing tcp/ip protocol, methods can be called through the network)
Dynamic
Multithreading
Security (anti-virus, anti-tampering)
Robustness