I was going through a list of articles available on the INETA website. I came across an article with the heading “Why C # is sharp and why is VB.NET basic?” Hmmm… However, the author has no intentions of looking down upon VB. I have done quite a few projects in VB 6. I am still a VB enthusiast because what I like most about it, is its simplicity and ability to do amazing stuff with little effort (directly proportional to coding?? Ahem…).
A few days back, I had read an extensive comparison between 11 languages in the September 2004 edition of DIQ (Developer IQ http://www.developeriq.com). It was called “The Great Language Shootout”. The article tabulates the results with C# scoring an overall 68pts and Java landing at 65pts. The article also explains in detail about the evaluation process. These figures are clearly just indicators of a test process and cannot form the basis to decide the power and application of any language or its future.
Unable to resist the temptation, I decided to write a simple HelloWorld… nope not just World… HelloManagedWorld program in C#. Managed because, I’m using the .NET csc compiler.
The code:
using System;
class helloManagedWorld
{
static void Main()
{
Console.WriteLine("Hello Managed World!");
}
}
Some explanation:
The using System; directive references a namespace called System that is provided by the Microsoft .NET Framework class library. This namespace contains the Console class referred to in the Main method. Namespaces provide a hierarchical means of organizing the elements of one or more programs. A “using” directive enables unqualified use of the types that are members of the namespace. The “Hello Managed World!” program uses Console.WriteLine as shorthand for System.Console.WriteLine.
The Main method is a member of the class helloManagedWorld. It has the static modifier, and so it is a method on the class helloManagedWorld rather than on instances of this class.
The entry point for an application—the method that is called to begin execution—is always a static method named Main.
How to compile the geeky way (ie. if you only have the .NET Framework, without VS.NET):
I started off with some errors as usual... case sensitivity and some syntax problems…
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>csc helloWorld.cs
Microsoft (R) Visual C# .NET Compiler version 7.00.9466
for Microsoft (R) .NET Framework version 1.0.3705
Copyright (C) Microsoft Corporation 2001. All rights reserved.
helloWorld.cs(4,30): error CS1552: Array type specifier, [], must appear before
parameter name
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>csc helloWorld.cs
Microsoft (R) Visual C# .NET Compiler version 7.00.9466
for Microsoft (R) .NET Framework version 1.0.3705
Copyright (C) Microsoft Corporation 2001. All rights reserved.
error CS5001: Program 'helloWorld.exe' does not have an entry point defined
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>csc helloWorld.cs
Microsoft (R) Visual C# .NET Compiler version 7.00.9466
for Microsoft (R) .NET Framework version 1.0.3705
Copyright (C) Microsoft Corporation 2001. All rights reserved.
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>helloWorld
Hello World!
Wasn’t that simple enough? So this is just the beginning. Lets see where I go from here. :-)
Monday, April 18, 2005
Types in C#
First time I saw the C# code in a magazine, I thought, Another new language, new syntax, new keywords…more confusion”. But now I don’t think so. C# is not completely different from other languages speaking of its syntax and approach. Moving further on, I learnt about the data types in C#.
C# supports two kinds of types: value types and reference types. No big deal. The name says it all. In case of values types, the variable stores the value directly and in case of reference types, it stores the reference to the variable (address). Other concepts like possibility of two variables referencing the same object are possible as in the case of C++.
A sample program to understand the types:
using System;
class ClassObj
{
public int num = 0;
}
class ClassTest
{
static void Main()
{
int x = 0;
int y = x;
y = 101;
ClassObj ref1 = new ClassObj();
ClassObj ref2 = ref1;
ref2.num = 999;
Console.WriteLine("Values: {0}, {1}", x, y);
Console.WriteLine("Refs: {0}, {1}", ref1.num, ref2.num);
}
}
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>csc D:\cstypes.cs
Microsoft (R) Visual C# .NET Compiler version 7.00.9466
for Microsoft (R) .NET Framework version 1.0.3705
Copyright (C) Microsoft Corporation 2001. All rights reserved.
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>cstypes
Values: 0, 101
Refs: 999, 999
An interesting thing that I’ve observed is the method used to print the formatted output in Console.WriteLine
Console.WriteLine takes a variable number of arguments. The first argument is a string, which may contain numbered placeholders like {0} and {1}. Each placeholder refers to a trailing argument with {0} referring to the second argument, {1} referring to the third argument, and so on. Before the output is sent to the console, each placeholder is replaced with the formatted value of its corresponding argument.
C# supports two kinds of types: value types and reference types. No big deal. The name says it all. In case of values types, the variable stores the value directly and in case of reference types, it stores the reference to the variable (address). Other concepts like possibility of two variables referencing the same object are possible as in the case of C++.
A sample program to understand the types:
using System;
class ClassObj
{
public int num = 0;
}
class ClassTest
{
static void Main()
{
int x = 0;
int y = x;
y = 101;
ClassObj ref1 = new ClassObj();
ClassObj ref2 = ref1;
ref2.num = 999;
Console.WriteLine("Values: {0}, {1}", x, y);
Console.WriteLine("Refs: {0}, {1}", ref1.num, ref2.num);
}
}
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>csc D:\cstypes.cs
Microsoft (R) Visual C# .NET Compiler version 7.00.9466
for Microsoft (R) .NET Framework version 1.0.3705
Copyright (C) Microsoft Corporation 2001. All rights reserved.
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>cstypes
Values: 0, 101
Refs: 999, 999
An interesting thing that I’ve observed is the method used to print the formatted output in Console.WriteLine
Console.WriteLine takes a variable number of arguments. The first argument is a string, which may contain numbered placeholders like {0} and {1}. Each placeholder refers to a trailing argument with {0} referring to the second argument, {1} referring to the third argument, and so on. Before the output is sent to the console, each placeholder is replaced with the formatted value of its corresponding argument.
Simple Basic Concept in C#
It is always better to understand these concepts with an example rather than trying to understand paragraphs of explanation.
Example:
class sharpTest
{
static void Main()
{
string s = "Sunil";
string t = string.Copy(s);
Console.WriteLine(s == t);
Console.WriteLine((object)s == (object)t);
}
}
Output:
True
False
Inference:
Two expressions of type object are considered equal if both refer to the same object, or if both are null.
Two expressions of type string are considered equal if the string instances have identical lengths and identical characters in each character position, or if both are null.
Type conversions are similar to C++. Implicit conversions like int to long are done without any loss of data. Explicit conversions are done with a cast expression.
Arrays in C#
As usual, single-dimensional and multi-dimensional arrays are supported.
// Creates a single-dimensional array of 5 elements
int[] arr = new int[5];
What is to be noted is that arrays are also reference types and hence have to be explicitly allocate the memory by specifying the size of the array.
// Some more arrays
int[,,] a3; // 3-dimensional array of int
int[][] j2; // "jagged" array: array of (array of int)
int[][][] j3; // array of (array of (array of int))
Type system unification
class Test
{
static void Main() {
Console.WriteLine(3.ToString());
}
}
All types including value types are derived from the type object. It is possible to call object methods on any value, even values of “primitive” types such as int.
Example:
class sharpTest
{
static void Main()
{
string s = "Sunil";
string t = string.Copy(s);
Console.WriteLine(s == t);
Console.WriteLine((object)s == (object)t);
}
}
Output:
True
False
Inference:
Two expressions of type object are considered equal if both refer to the same object, or if both are null.
Two expressions of type string are considered equal if the string instances have identical lengths and identical characters in each character position, or if both are null.
Type conversions are similar to C++. Implicit conversions like int to long are done without any loss of data. Explicit conversions are done with a cast expression.
Arrays in C#
As usual, single-dimensional and multi-dimensional arrays are supported.
// Creates a single-dimensional array of 5 elements
int[] arr = new int[5];
What is to be noted is that arrays are also reference types and hence have to be explicitly allocate the memory by specifying the size of the array.
// Some more arrays
int[,,] a3; // 3-dimensional array of int
int[][] j2; // "jagged" array: array of (array of int)
int[][][] j3; // array of (array of (array of int))
Type system unification
class Test
{
static void Main() {
Console.WriteLine(3.ToString());
}
}
All types including value types are derived from the type object. It is possible to call object methods on any value, even values of “primitive” types such as int.
Tuesday, April 05, 2005
C# versus VB.NET
Hi
many of our friends wanna know about this question, so i would like to answer this questions
Q: any advantages C# would have over Visual Basic (VB) in terms of the framework?
Answer: Regarding C# vs. Visual Basic, it really primarily comes down to what you already know and are comfortable with. It used to be that there was a large perf difference between VB and C++, but since C# and VB.NET use the same execution engine, you really should expect the same perf. C# may have a few more "power" features (such as unsafe code), and VB.NET may be skewed a bit more towards ease of use (e.g. late bound methods calls), but the differences are very small compared to what they were in the past.
Q: Okay, can we contrast C# with VB.NET? Questions usually come in the form of "I know you guys say VB.NET and C# let you do the same thing, but C# was designed for the CLR, so I don't believe you when you say VB.NET is just as good."
Answer: Regarding C# versus VB.NET, the reality is that programmers typically have experience with either C++ or VB, and that makes either C# or VB.NET a natural choice for them. The already existing experience of a programmer far outweighs the small differences between the two languages.
Q: Could you discuss the security of the config files. I have seen a lot of concern that since they are simple XML files, they can be hacked into easily.
Answer: We do block all access to the config files from remote users. However, I think the concern people have is whether a rogue user who gets access to the config file can modify and take over things. Note that this problem exists with ASP today as well, in that the metabase APIs can be written to, which would effectively do the same thing. However, there are some things that you can do to reduce this problem. Specifically, with ASP.NET we support the ability to "lock down" settings at a parent directory. For example, you might want to lock down the security identity of the worker process (i.e.: the username it runs under) at the machine level and then restrict sub-applications' abilities to override it.
Q: I've seen a lot of concern that data can be passed page to page (ASP to and from ASP.NET).
Answer: Since we really use standard Web techniques, passing info page to page should not be a problem. However, page to page in ASP and ASP.NET typically assumes services that are provided by each, such as session and application state. These services are not shared, and so you can't rely on them. I have a list of things you can do to ease migration of ASP code to ASP.NET.
1. Use only a single language within the ASP application. Don't intermix VBScript and JScript together in the same page (in general a bad programming practice with ASP, but also a migration issue for ASP.NET in that we now require only one inline <% %> language.
2. Explicitly declare all of ASP page functions within a
many of our friends wanna know about this question, so i would like to answer this questions
Q: any advantages C# would have over Visual Basic (VB) in terms of the framework?
Answer: Regarding C# vs. Visual Basic, it really primarily comes down to what you already know and are comfortable with. It used to be that there was a large perf difference between VB and C++, but since C# and VB.NET use the same execution engine, you really should expect the same perf. C# may have a few more "power" features (such as unsafe code), and VB.NET may be skewed a bit more towards ease of use (e.g. late bound methods calls), but the differences are very small compared to what they were in the past.
Q: Okay, can we contrast C# with VB.NET? Questions usually come in the form of "I know you guys say VB.NET and C# let you do the same thing, but C# was designed for the CLR, so I don't believe you when you say VB.NET is just as good."
Answer: Regarding C# versus VB.NET, the reality is that programmers typically have experience with either C++ or VB, and that makes either C# or VB.NET a natural choice for them. The already existing experience of a programmer far outweighs the small differences between the two languages.
Q: Could you discuss the security of the config files. I have seen a lot of concern that since they are simple XML files, they can be hacked into easily.
Answer: We do block all access to the config files from remote users. However, I think the concern people have is whether a rogue user who gets access to the config file can modify and take over things. Note that this problem exists with ASP today as well, in that the metabase APIs can be written to, which would effectively do the same thing. However, there are some things that you can do to reduce this problem. Specifically, with ASP.NET we support the ability to "lock down" settings at a parent directory. For example, you might want to lock down the security identity of the worker process (i.e.: the username it runs under) at the machine level and then restrict sub-applications' abilities to override it.
Q: I've seen a lot of concern that data can be passed page to page (ASP to and from ASP.NET).
Answer: Since we really use standard Web techniques, passing info page to page should not be a problem. However, page to page in ASP and ASP.NET typically assumes services that are provided by each, such as session and application state. These services are not shared, and so you can't rely on them. I have a list of things you can do to ease migration of ASP code to ASP.NET.
1. Use only a single language within the ASP application. Don't intermix VBScript and JScript together in the same page (in general a bad programming practice with ASP, but also a migration issue for ASP.NET in that we now require only one inline <% %> language.
2. Explicitly declare all of ASP page functions within a