I. INPUT and OUTPUT statementsThe main input and output statements of the main function are:Console.Write (); Output statement, do not wrap lineConsole.WriteLine (); Output statement, wrap lineConsole.read (); Input statement, does not wrap
Installation of JDK:
Download, install
Configuring Environment variables
A) path:.; %java_home%\bin;b) installation directory for JAVA_HOME:JDKc) classpathJDK and JRE and JVM:JAVA program run Process:
Compiling Javac:
1. The file name of the source code must match the class name of the public class, and there can be at most one common class (public) in a source code file
2. NOTES: 3 kinds
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Java data types fall into three main categories, namely, Boolean , character , and numeric . The numerical type is divided into integral type and floating point type. The basic data types of Java (8 types) are Boolean Boolean (1 bytes), character
Watch the video review Java for some time. Although the things I do now are net, I haven't forgotten to review Java.More probably here.Naming rules for Java variables:(A) Composition rules:1: English uppercase and lowercase letters2: Number3:$ and _(
Java four class eight basic data typesFirst class: integer byte short int long Type II: float float doubleClass III: Logical Boolean (it has only two values desirable true false)Class Fourth: Character CharBytes:Boolean Boolean 1/8 byte byte type
Well, this should have been sent before OOP, do not care, a replacement, this article will only be a basic outline of javase grammar, I will be in the recent new open a new pit, that is, the Java EE series, there will be CPP (compared to C + +, I
In Java, there are eight basic data types:
1) The 31 Power of int 4 bytes (byte)-2 to the 31 power of 2-1
2) short 2 bytes (byte)-the 15th power of 2 to the 15th power of 2-1
3) long 8 bytes (byte)-power 63 of 2 to power 63 of 2-1
4) byte 1 byte-the
Java series (3)-basic syntax and java syntax
1. Keywords
Features: All lowercase letters
2. identifier
(1) It is the character sequence that names such as class, interface, and method.
(2) composition rules:
A: uppercase/lowercase letters
OverviewThe Java language has been 22 years since the launch of Sun in 1995 and is now one of the most used Languages. Java is also a relatively easy to get started language, my first contact with the language is Java. Java Development. The core of
I. Method of type conversion and precautions:1.Convert to boolean:(1) Using two non-operations(!) :!! 5 ==> true(2) Use a Boolean constructor:New Boolean (5) ==> trueConvert value to boolean typeFalse:0,+ 0,-0,NaN,""(Null String), Undefined,
Basic data type:
Basic data types
Size
Range
Default value
int (shaping)
32
-2147483648~2147483648
0
Long (length shaping)
64
-9233372036854477808~92333720368544778
One or two binary number1, the highest bit is 0, indicates a positive number, the highest bit is 1, indicates a negative number. 2, the corresponding negative and positive conversion between the way: through the complement of the conversion, that is:
1. Abstraction, inheritance, encapsulation, polymorphism2. Number of bytes for the base data typeByte:1, Int:4, Char:2, Long:8, Float:4, Double:8, Boolean:1 and Short:23.String, the difference between stringbuffer,stringbuilderWhen strings are less
Does the 11,java have a long double type or more accurate than a double?===========Does the 11,java have a long double type or more accurate than a double?Basic data types for JavaData type size range default valueByte (bytes) 8-128-127 0Shot (short-
Data typeThere are eight basic types:Integer: Byte (1), short (2), int (4), Long (8)Float type: Float (4), double (8)Character type: char (2)Boolean type: Boolean (1)VariableVariables are used to store data. In Java, variables must be declared. In
2.1 Manipulating objects with handlesEverything in Java is "considered" as an object. The way the object is manipulated is through a handle to the object (also known as a reference or pointer). But the handle does not necessarily point to the object,
numeric types are automatically converted to strings when the data for a string, numeric type is additive.When the IF condition is inside, the result is automatically converted to a Boolean type of data.1 To force type conversions:
File class:Java.io.File Basic methods;Gename: Get file nameGetPath: Get File pathLength: Get File sizeIsdirectory: Judging If this thing is not a directoryIsfile: Judging this thing is not a fileListfiles: Gets all the files and folders under the
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