Chapter 1 Introduction to Computers, Programs, and Java
A computer is an electronic device that stores and processes data. A computer
数据结构与算法考研真题includes both hardware and外国网页设计免费模板 software. In general, hardware is the physical aspect of
the computer that can be seen, and software is the invisible instructions that control
the hardware and make it work. The hardware of a computer consists of a CPU,
swit语句cache, memory, hard disk, floppy disk, monitor, printer, and communication devices.
The machine language is a set of primitive instructions built into every computer.
Assembly language is a low-level programming language in which a mnemonic is
used to represent each of the machine language instructions. The high-level
languages are English-like and easy to learn and program.
The operating system (OS) is a program that manages and controls a computer’s
activities. The examples of OS are Windows 98, NT, 2000, XP, or ME. Windows.
Application programs such as an Internet browser and a word processor run on top of
an operating system.
100 in decimal => 64 in hex
100 in decimal => 01100100 in binary
4340 in decimal => 10F4 in hex
4340 in decimal => 1000011110100 in binary
2000 in decimal => 7D0 in hex
2000 in decimal => 11111010000
5.
1000011001 in binary => 219 in hex
1000011001 in binary => 537 in decimal
100000000 in binary => 100 in hexjava经典上机编程题>activity是什么
100000000 in binary => 256 in decimal
100111 in binary => 27 in hex
100111 in binary => 39 in decimal
6.
FEFA9 in hex => 1044393 in decimal
FEFA9 in hex => 11111110111110101001 in binary
93 in hex => 147 in decimal
chart控件大红叉
93 in hex => 10010011 in binary
2000 in hex => 8192 in decimal
1.
2.
3.
4.
2000 in hex => 10000000000000 in binary
Developed by a team led by James Gosling at Sun Microsystems in 1991. Originally
called Oak, it became Java in 1995 when it was redesigned for developing Internet
applications.
Java can run on any platform with a Java Virtual Machine. The minimum requirement
is the Java Runtime Environment, free from the www.javasoft.
The input is the Java source code and the output is the Java bytecode (if compiled
successfully).
JBuilder by Borland, Sun ONE Studio by Sun, Café by WebGain, Visual Age for
Java by IBM are the tools for developing Java programs, not dialects of Java. These
tools make developing Java programs easier and more productive.
HTML is a markup language for displaying static Web pages. Java is a full-fledged
programming language that can be used to develop dynamic Web pages. The Java
programs that run from a Web browser are called applets. Java applets must be
embedded in HTML files using the <applet> tag.
Keywords have specific meaning to the compiler and cannot be used for other
purposes in the program such as variables or method names. Examples of keywords
are class, static, and void.
Java source code is case sensitive. Java keywords are always in lowercase.
The source file extension is .java and the bytecode file extension is .class.
Comments are used to document what a program is for and how a program is
constructed. Comments help the programmers or users to communicate and
understand the program. Comments are not programming statements and are ignored
by the compiler. In Java, comments are preceded by two forward slashes (//) in a line
or enclosed between /* and */ in multiple lines. When the compiler sees //, it ignores

版权声明：本站内容均来自互联网，仅供演示用，请勿用于商业和其他非法用途。如果侵犯了您的权益请与我们联系QQ:729038198，我们将在24小时内删除。