Get Oracle Version

Oracle > Version

V$VERSION displays version numbers of core library components in the Oracle Database.

Example:

select * from v$version

Result:

Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production

Sealed modifier C#

C# > Modifiers > sealed

Sealed modifier prevents other classes from inheriting from it.
Also you can use the sealed modifier on a method or property that overrides a virtual method or property in a base class. This enables you to allow classes to derive from your class and prevent them from overriding specific virtual methods or properties.

Examples

1. Sealed class
    class C1 { }
    sealed class C2 : C1 { }
    class C3 : C2 { } // Error : cannot derive from sealed type C2

2. Sealed method

    class A

    {
        protected virtual void F() { }
        protected virtual void F1() { }
    }
    class B : A
    {
        sealed protected override void F() { }
        protected override void F1() { }
    }
    class C : B
    {
        protected override void F() { } //Error cannot override inherited member because it is sealeD
        protected override void F1() { }
    }

const c#

C# > Modifiers > const

The const specifies that the value of the field or the local variable is constant and it cannot be modified.
 
The const keyword differs from the readonly keyword. A const field can only be initialized at the declaration of the field. A readonly field can be initialized either at the declaration or in a constructor.

Example:

class SampleConst
    {
        public int x;
        public int y;
        public const int c1 = 1;
        public const int c2 = c1 + 5;

        public SampleConst(int v1)

        {
            x = v1 + c1;
            y = x + c2;
        }
    }

sbyte keyword C#

C# > Types > sbyte

The sbyte keyword is an integral type.
Range: -128 to 127
Size: Signed 8-bit integer

Example:

sbyte k = 127; // ok

k = 128;      // Error     1      Constant value '128' cannot be converted to a 'sbyte' 

int keyword C#

C# > Types > int

The int keyword is an integral type.
Range: -2,147,483,648 to 2,147,483,647
Size: Signed 32-bit integer

Example:

int i = 100;

int x = 3.0; // Error 1 Cannot implicitly convert type 'double' to 'int'. An explicit conversion exists (are you missing a cast?)

int y = (int)3.0; // OK: explicit conversion.

Stopwatch C# Example

C# > Diagnostics > Stopwatch 

Stopwatch measures elapsed time.

The Stopwatch measures elapsed time by counting timer ticks in the timer mechanism. If the installed hardware and operating system support a high-resolution performance counter, then the Stopwatch class uses that counter to measure elapsed time.

Example:


Stopwatch sw = new Stopwatch();
sw.Start();
Thread.Sleep(500);
sw.Stop();
TimeSpan ts = sw.Elapsed;
MessageBox.Show("Elapsed time " + ts.ToString());

C# operators

C# > Operators

C# operators are symbols that specify which operations to perform in an expression.

• []
• => Lambda
• ?: Ternary
• ()
• ??
• %