If Statement

Code Fragment can be executed only if a certain condition is met.

Syntax

if(condition) { // Code to execute if condition is met. }

condition has a boolean type (true or false).

Basic Example

using System; namespace csharp { class Program { static void Main(string[] args) { if (true) { Console.WriteLine("a"); } if (false) { Console.WriteLine("b"); } bool varName = true; if (varName) { Console.WriteLine("c"); } } } }

Output:

a c

if condition is true - execute the code inside if fragment.

Comparison Operators

Operator	Description	Examples	Result
==	Equal to	5 == 5	true
		4 == 5	false
		3 + 2 == 5	true
!=	Not equal to	7 != 5	true
		4 != 4	false
		true != false	true
>	Greater than	5 > 0	true
		5 > 5	false
		10 > 0	true
>=	Greater than or equal to	3 >= 3	true
		5 >= 4	true
		3 >= 5	false
<	Less than	3 < 5	true
		5 < 6	true
		5 < 5	false
<=	Less than or equal to	2 <= 0	false
		5 <= 5	true
		5 < 1	false

Let's create a program that uses comparisons operators.

Determine whether person is adult (age >= 21) or child (age < 13) depending on his/her age.

using System; namespace csharp { class Program { static void Main(string[] args) { int age = 25; if (age >= 21) { Console.WriteLine("Adult"); } if (age < 13) { Console.WriteLine("Child"); } } } }

Output:

Adult

Since age is greater than 21, line 13 executes.

Because age is not less than 13, line 18 is not executed.