JAVA First Lesson

JAVA First Lesson

Computer recognition: binary, octal, hex

Binary to represent high and low voltages, similar to the transmitters during the anti-Japanese war. 2 -binary storage

8 binary and in- system: Calculator, in the calculation of a certain temporary storage,8 -bit or block Storage

after hexadecimal, there is no number , so it is replaced by letters,a,b,c ...

and the final computer only recognizes 2 of the data in the system.

Unit of measurement of a computer

Conversion between computer binaries

to put it simply, how to make the number of our system into a 2- digit number that the computer can recognize, divided by 2 until the last equals 1, and then from the last 1 start to connect all the remainder together.

How to convert 2 into ten , using the method of weight, for example , 110101, its algorithm is:

1x2 0 - Time Square +1x2 of 3 +1x2 4 the 5 -square =53 of the second- party +1x2

2-binary to 8 -binary tables,

2 binary to The Operation table of the binary

The number of the 8 binary is represented by a 3 -bit 2 binary number, and The number of the binary is 4 bits. 2 binary to indicate

Summary Chart

There are three kinds of symbolic representations in the computer

1, original code

2, complement

3, anti-code

Example:

Original code:11101101

Anti-code:00010010

+13

original code, anti-code, complement ; 00001101

-13

Original code:10001101(first, also highest to indicate positive and negative numbers)

Anti-code:11110010

Complement:11110011

Introduction to JAVA

three main categories of JAVA

Programming language Leaderboard

JBK Directory Analysis

JAVA Code

New JAVA Project, when named for the name, the name can only contain letters, numbers and underscores, and the first character cannot be a number.

{}: is a scope,

System.out.,printin (" This is my first JAVA program "); --To output text content to the console, you must enclose the double quotation marks inside the brackets, and if you join an operation, you do not have to add double quotes.

In the output operation, for the result, neither four or five, if one side with a decimal, the result is a decimal.

JAVA First Lesson