Enums in C#

Enums in C#


Enums are basically a set of named constants. i.e. these are basically a group of named constants defined under a common name.
Enums are value types and are created on the stack and not on the heap.

Eg:

using System;
public enum Colors
{
red,
green,
blue,
}


public class Mainclass
{
public static void Main()
{
string color = Colors.red.ToString();
Console.WriteLine("Color is:" + color);
int id = (int)Colors.blue;
Console.WriteLine("Color value:" + id);
}
}


Each enum type has a corresponding value type called underlying type of the enum type.

Unsafe Code ( Using Pointer) in C#

Unsafe Code ( Using Pointer in C#)

C#.NET hides most of memory management, but in some cases we need direct access to the memory, then unsafe code is used.


Eg:
using System;
class Mainclass
{
public static void Main()
{
int a = 5;

unsafe
{
int* ptr;
ptr = &a;
*ptr = 20;
}
Console.WriteLine("a = " + a);
}
}



Eg:

using System;
unsafe class Mainclass
{
public static void Main()
{
int a = 5;
int* ptr;
ptr = &a;
*ptr = 20;


Console.WriteLine("a = " + a);
}
}

Parameter Arrays in C#

Parameter array.


Parameter arrays allows us to pass a variant  number of arguments into a method. All incoming arguments will consider as a single dimensional array. Have a look on the following example.
using System;


class Mainclass
{
public static void Main()
{
Test obj = new Test();
obj.Add(10, 20);
obj.Add(10, 20, 30);
obj.Add(1, 2, 3, 4, 5, 6);
}
}


class Test
{
public void Add(params int[] ar)
{
int sum = 0;
foreach (int i in ar)
{
sum = sum + i;
}
Console.WriteLine("Sum : " + sum);
}
}

Reference Parameters in C#

Reference Parameter


These are input/output parameters; they can be used for passing value into a function as well as to get back value from a function.

using System;
class Test
{


public void Inc(ref int a) // here a is a reference parameter. It refer the same memory address of passing arguement.
{
a = a + 10;
Console.WriteLine(a);
}
}



class Mainclass
{
public static void Main()
{
int x = 10;
Test obj = new Test();
obj.Inc(ref x); // arguement x and parameter a will be using the same memory reference.
Console.WriteLine("From Main " + x);
}
}

Output Parameters in C#

Output Parameter


A function can return only a single value. But when we using output parameters it is possible to return multiple values.
Note: output parameters must be assigned with value before leaving method, otherwise it will results in a compilation error.
Eg

using System;
class Test
{


public void Cal(int a, int b, out int c, out int d) // a and b are input parameters. c and d are output parameters.
{
c = a + b;   // set value for output parameter c.
d = a - b;   // set value for output parameter d.}


}

class Mainclass
{
public static void Main()
{
int n1 = 10, n2 = 30, sum, dif;
Test obj = new Test();
obj.Cal(n1, n2, out sum, out dif);
Console.WriteLine("Sum is {0} and Difference is {1} ", sum, dif);
}
}

Input Parameters in C#

Input Parameter


It is used to receive values, means it just pass values.

e.g

using System;
class Test
{
public void Increment(int a) // here a is an input parameter it just takes value from the Main method.
{
a = a + 10;
Console.WriteLine("a=" + a);
}
}


class MainClass
{
public static vod Main()
{
int x = 10;
Test obj = new Test();
obj.Increment(x); // passing value into the method.
Console.WriteLine("x=" + x);
}
}