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   ► KBTo/From GuidesJavaLanguage Basics  Print This     

Cross Ref > Language Basics

By Mike Prestwood

Java versus C#: A side by side comparison between Java and C#.

 
Language Basics
 

Language basics is kind of a catch all for absolute beginner stuff. The items (common names) I chose for language basics is a bit random and include items like case sensitivity, commenting, declaring variables, etc.

Case Sensitivity

[Other Languages] 

Languages Focus

Case sensitiviy in this case is referring to commands and variable names. For example, are "printf" and "PrintF" equivalent? Are fullname and FullName equivalent? When you create commands, operations, methods, or variables should you worry about case?

Java:   Yes

Java is case sensitive.

Customary casing:

  • Classes - Initial Caps (Pascal Casing)
  • Variables - Initial lowecase (Camel case)
  • Methods - Initial lowecase (Camel case)
More Info / Comment
C#:   Yes

In C# commands and variable names are case sensitive. The following does NOT:

messagebox.Show("hello");  //Does not compile!

The first time you type any other case for commands or variables, VS.Net will change it to the accepted or defined case. For example, if you type messagebox.show it is converted to MessageBox.Show. Once corrected, you can break it again by editing MessageBox to messagebox and the compiler will give you an error.

Syntax Example:

The following code works:

MessageBox.Show("hello");




Code Blocks

[Other Languages] 

Languages Focus

The rules for code blocks within a language dictate where you can declare variables, how you "bracket" code, etc.

Java:   { }

Curly braces are used to bracket code blocks including classes and the methods within a class.

For Java, JavaScript, PHP, and C++, I prefer to put the first { at the end of the first line of the code block as in the example above because I see moreJava codeformatted that way.

Syntax Example:
public class Dog {
  public bark() {
    System.out.println("Ruff");
  }
}
C#:   { }

C# uses braces {} to indicate a code block of more than one line. For one line of code, the braces are optional.

I prefer to put the opening { and the closing } on their own line only because most of the examples I see do this. As opposed to C++, Java, and JavaScript where I put the opening bracket at the end of the first line (which I actually prefer).

Syntax Example:
int DoSomething()
{
 int a = 1;
 int b = 2;
 return a + b;
}




Comments

[Other Languages] 

Languages Focus

Commenting code generally has three purposes: to document your code, for psuedo coding prior to coding, and to embed compiler directives. Most languages support both a single line comment and a multiple line comment. Some languages also use comments to give instructions to the compiler or interpreter.

Java:   // or /* ... */

Commenting Code
Java uses "//" for a single line comment and /* */ for a multiple line comment.

Syntax Example:
//Single line comment in MS (not ANSI compliant so do NOT use).
/* ANSI compliant single line comment. */
/*
Multiple line
comment.
*/
/*
* This is another popular way 
* to write multi-line comments.
*/
C#:  "Multiple Line Comment" // or /* */

Commenting Code
C# uses "//" for a single line comment and /* */ for a multiple line comment.

Syntax Example:
//Single line comment.

/*
Multiple line
comment.
*/




Constants

[Other Languages] 

General Info: Computer Language Constants

A constant is just like a variable (it holds a value) but, unlike a variable, you cannot change the value of a constant.

[Not specified yet. Coming...]
C#:   const

In C#, you define constants with the const keyword.

All constants are part of a class (no global constants) but you can make a constant public and have access to it using ClassName.ConstantName so long as you have added the class to the project. This works even without creating the class as if the public constants were static, but you cannot use the static keyword.

Constants must be of an integral type (sbyte, byte, short, ushort, int, uint, long, ulong, char, float, double, decimal, bool, or string), an enumeration, or a reference to null.

Syntax Example:  
public class Convert : Object
{
  public const string kName = "Mike";
 
  //You can declare multiple of the same type too:
  const Double kFeetToMeter = 3.2808, kMeterToFeet = .3048;
}




End of Statement

[Other Languages] 

Languages Focus

In coding languages, common End of statement specifiers include a semicolon and return (others exist too). Also of concern when studying a language is can you put two statements on a single code line and can you break a single statement into two or more code lines.

Java:   ;
Syntax Example:
System.out.println("Hello");
C#:   ;

C# uses a semicolon ";" as an end of statement specifier and you can put multiple statements on a single line of code if you wish as well as split a single statement into two or more code lines.

Syntax Example:  
Console.WriteLine("Hello1");
Console.WriteLine("Hello2");
Console.WriteLine("Hello3");

//Same line works too:
Console.WriteLine("Hello4"); Console.WriteLine("Hello5");
 
//Two or more lines works too: 
Console.
  WriteLine
("Hello6");





Literals

[Other Languages] 

General Info: Programming Literals

A value directly written into the source code of a computer program (as opposed to an identifier like a variable or constant). Literals cannot be changed. Common types of literals include string literals, floating point literals, integer literals, and hexidemal literals. Literal strings are usually either quoted (") or use an apostrophe (') which is often referred to as a single quote. Sometimes quotes are inaccurately referred to as double quotes.

Languages Focus

In addition to understanding whether to use a quote or apostrophe for string literals, you also want to know how to specify and work with other types of literals including floating point literals. Some compilers allow leading and trailing decimals (.1 + .1), while some require a leading or trailing 0 as in (0.1 + 0.1). Also, because floating point literals are difficult for compilers to represent accurately, you need to understand how the compiler handles them and how to use rounding and trimming commands correctly for the nature of the project your are coding.

Java:   quote

String literals are quoted as in "Prestwood". If you need to embed a quote use a slash in front of the quote as in \".

To specify a floating point literal between 1 and -1, you can preceed the decimal with a 0 or not (both work). In other words, preceding and following decimals are allowed (both 1. and 1.0 work as well as .1 and 0.1). In general, Java follows the IEEE 754 Binary Floating-Point Arithmetic standard.

Syntax Example:

System.out.println("Hello");
System.out.println("Hello \"Mike\".");
  
//Does Java evaluate this simple
//floating point math correctly? No!
if ((.1 + .1 + .1) == 0.3) {
System.out.println("Correct");
} else {
System.out.println("Not correct");
}
C#:   quote

String literals are quoted as in "Prestwood". If you need to embed a quote use a slash in front of the quote as in \".

To specify a floating point literal between 1 and -1, you can preceed the decimal with a 0 or not (both work). In other words, preceding decimals are allowed (both .1 and 0.1). Trailing decimals are not allowed.

Syntax Example:
Console.WriteLine("Hello");
Console.WriteLine("Hello \"Mike\".");
 
//Does C# evaluate this simple
//floating point math correctly? No! 
if ((0.1 + 0.1 + 0.1) == 0.3)
{
MessageBox.Show("Correct");
}
else
{
MessageBox.Show("Not correct");
}




Variables

[Other Languages] 

Languages Focus

A variable holds a value that you can use and change throughout your code so long as the variable is within scope. With variable declaration, you not only want to know the syntax of how you declare a variable but you also want to know where. Are you allowed to declare a variable inline? What are the available scopes: local vs. global. Can you assign a value at the same time you declare a variable?

Java:   int x = 0;

Variable names are case sensitive.

The Java basic types are boolean, byte, short, int, long, float, double, and char. You can also declare a variable to hold a particular instance of a class such as String.

Syntax Example:

C++, Java, and C# all use C-like variable declaration.

int a;
int a, b;
int age = 43;
String FullName;
C#:   Int16 x=0;

C++, Java, and C# all use C-like variable declaration.

C# has C-like variable declaration and although variables are case sensitive, VS.Net will auto-fix your variable names to the defined case.

C# offers many variable types. Some common types used include short, intlong, float, double, decimal, Int16, UInt16, Int32, Int64, string, and bool.

You can also specify the value when you declare a variable as in:

String FirstName = "Mike";
String LastName = "Prestwood";
Int16 Age = 42;
Syntax Example:
string FullName;
int16 Age;
double Weight;
 
FullName = "Mike Prestwood";
Age = 32;
Weight = 154.4;




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