C,c#,javascript,java

	C	C#	Javascript	Java
Case sensitive	Is	Is	Is	Is
Statement end	Semicolon	Semicolon	Semicolon, optional	Semicolon
Line Comment	//	//	//	//
Block annotations	/**/	/**/	/**/	/**/
Description Comment		///		/** Start, * * End
Identifier	Letters, numbers, underscores, must start with a letter or underscore	Letters, numbers, underscores, must start with a letter or underscore	Must start with a letter,& and _ can also, but not recommended	Letters, numbers, underscores, dollar characters, must start with a letter, underscore, or dollar symbol
Constant	#define CONST PI=3.14 Habitually, the constant name is all uppercase.	Const FLOAT PI=3.14 MSDN recommends using Pascal to name	No constants	Final Double pi=3.14 Habitually, the constant name is all uppercase.
Data type	Base type: integer, float, character, enum Constructed type: array, struct, community Pointer type Empty type	Built-in 15 predefined types 13 Types of values 2 reference types, object,string	Dynamic types, the same variables can be used for different types. Number, String, Boolean, Array, object, null,undefined	Built-in types and reference types. Available in 8 basic types, 6 numeric types, 1 character types, and 1 Boolean types.
String	String has end tag		can be enclosed in single or double quotation marks. Quotation marks use: does not match the characters used to include. For example, enclose a single quotation mark, and the interior can contain double quotes.
Operator	Comparison operators ==,!=,<,>,<=,>=	comparison Operators ==,!=,<,>,<=,>=	comparison Operators ==,!=,<,>,<=,>=	comparison Operators ==,!=,<,>,<=,>=
	logical operators !,&&,| |	logical Operators !,&&,| |	logical Operators !,&&,| |	logical Operators !,&&,| |
	pointer Operators *,&	nullable operator ?	congruent operators, values and types are congruent ===
	No string join operator	String Join operators +	String Join operators +	String Join operators +
Flow control	If...else If...else ...	If...else If...else ...	If...else If...else ...	If...else If...else ...
	For ...	For ...	For ...	For ...
	While ...	While ...	While ...	While ...
		Foreach...	for (x in obj)	for (an int x in array)
Array definition	int a[10]={1,2,3,4,5};	Int[] A=new int[10];	var a=new Array (10);	Int[] A=new int[10];
	int a[2][3]={{1,2,3},{4,5,6}}	int[,] a=new int [2,3];		Int[][] A=new int[2][3];

C,c#,javascript,java