C#- Programming Guide | Starting Phase Learning(9)

Here, we will learn about the Conditional Statements in C#.

A statement that can be executed based on a condition is known as a “Conditional Statement”.
Less than: a < b
Less than or equal to a <= b
Greater than: a > b
Greater than or equal to a >= b
Equal to a == b
Not Equal to: a != b
You can use these conditions to perform different actions for different decisions.

We have different conditional statements in c# to handle all the operations:
if and nested if statement
switch and nested switch statement
if-else and nested if-else Statement
** We also use ternary and Lambda expressions to make the code more effective.

if Statement:
Use the if statement to specify a block of C# code to be executed if a condition is True. C# is case sensitive so writing uppercase letters (If or IF) will generate an error.

else Statement:
Use the else statement to specify a block of code to be executed if the condition is False.

    static void Main(string[] args)
    {

        int a = 10;
        int b = 20;
        int c;
        if(b>a) //if block
        {
            c = a + b;//performs addition
        }
        else //else block
        {
            c = a - b;//performs substraction
        }
        Console.WriteLine("The value of C is " + c);

        Console.ReadKey();

    }

Nested if:
If within if statement is nested if

if(condition)
{
statement
if(condition)
{
statement
statement
}
}

Nested if-else:
If else within if or else statement is Nested if-else.

if(condition)
{
//statement
if(condition)
{
//statement
//statement
}
else
{
//statement
}
}

If -else-if :

if(condition)
{
//statement
}
else if(condition)
{
//statement
//statement
}
else
{
//statement
}

Sample example illustrating all if operations:

        static void Main(string[] args)
        {

            int a = 10;
            int b = 20;
            int c;

            #region if operation
            if (a > b && a != 15)// if with and operators
            {
                a += b;
                a--;
                Console.WriteLine(++a);
            }
            #endregion

            #region nested if operation
            if (a > 10)// if condition
            {
                a += b; //a= a +b;
                a--;   //unary operator
                if (a > 25)
                {
                    Console.WriteLine(++a);//printing the incremented value of a 
                }
            }
            #endregion

            #region  if-else operation
            if (a > 10)// if condition
            {
                a += b; //a= a +b;
                a--;   //unary operator
                Console.WriteLine(++a);//printing the incremented value of a 
            }
            else
            {
                Console.WriteLine(++b);//printing the incremented value of b
            }
            #endregion

            #region nested if-else operation
            if (a > 10)// if condition
            {
                a += b; //a= a +b;
                a--;   //unary operator
                if (a != 5)
                {
                    Console.WriteLine("a not equal to 5");//printing
                }
                else
                {
                    Console.WriteLine("a  equal to 5");//printing
                }
                Console.WriteLine(++a);//printing the incremented value of a 
            }
            else
            {
                Console.WriteLine(++b);//printing the incremented value of b
            }
            #endregion

            #region if else-if else
            if (a > 5)
            {
                Console.WriteLine(++a);//printing the incremented value of a
            }
            else if (a < b)
            {
                Console.WriteLine(++a);//printing the incremented value of a
            }
            else
            {
                c = a * b;
                Console.WriteLine(c);//printing the incremented value of c
            }
            #endregion
            Console.ReadKey();

        }

In the above sample, we can see nested if -else, so whenever we talk about if-else then if the condition in if is false then else gets executed.

If you have one statement for any conditional statement you can avoid braces (interpolation):
You can write

if(a >b)
Console.WriteLine(b);//printing the incremented value of b
else
Console.WriteLine(a);//printing the incremented value of a

**Switch Case operations will be seen in the next article.