- How do I calculate an MD5 hash from a string?
- What is the difference between const and static read-only
- What is a static constructor
- Does C# support multiple inheritances?
- What is the difference between System. String and System.StringBuilder classes?
- Can you inherit multiple interfaces?
- What is Overriding?
- What is Shadowing?
How do I calculate an MD5 hash from a string?
It is a common practice to store passwords in databases using a mixture. MD5 (defined in RFC 1321) is a standard hash algorithm, and using it from C# is easy.
Here’s an implementation of a method that converts a string to an MD5 hash, a 32-character string of hexadecimal numbers.
public string CalculateMD5Hash(string input)
{
// step 1, calculate MD5 hash from input
MD5 md5 = System.Security.Cryptography.MD5.Create();
byte[] inputBytes = System.Text.Encoding.ASCII.GetBytes(input);
byte[] hash = md5.ComputeHash(inputBytes);
// step 2, convert byte array to hex string
StringBuilder sb = new StringBuilder();
for (int i = 0; i < hash.Length; i++)
{
sb.Append(hash[i].ToString("X2"));
}
return sb.ToString();
}
An example call:
string hash = CalculateMD5Hash("abcdefghijklmnopqrstuvwxyz");
OUTPUT
C3FCD3D76192E4007DFB496CCA67E13B
To make the hex string using lower-case letters instead of upper-case, replace the single line inside the for loop with this line:
sb.Append(hash[i].ToString("x2"));
The difference is the ToString method parameter.
What is the difference between const and static readonly
The difference is that the value of a static read-only the field is set at run time and can thus be modified by the containing class, whereas the value of a const the field is set to a compile-time constant.
What is a static constructor?
It is a special type of constructor, introduced with C#. It gets called before creating the first object of a class(probably at the time of loading an assembly). See the example below.
public class SomeClass()
{
static SomeClass()
{
//Static members may be accessed from here
//Code for Initialization
}
}
Does C# support multiple inheritances?
No, Use interface
What is the difference between System. String and System.StringBuilder classes?
System. A string is an immutable, System.StringBuilder was designed to have a mutable string where a variety of operations can be performed.
Can you inherit multiple interfaces?
Yes, why not. Through Interface, we can achieve
What-is-overriding?
Process of creating different implementation of a method having the same name as a base class in a derived class. It implements Inheritance.
When we need to provide a different implementation than the provided by the base class, We define the same method with the same signatures in the derived class. The method must be Protected/Protected-Friend/Public for this purpose. (Base class routine can be called by Mybase.Method, base.Method).
What is Shadowing?
When the method is defined as Final/sealed in the base class and not overrideable, we need to provide a different implementation. This process is known as shadowing, uses shadows/new keyword.