YouTipCsharp If Else
# C# if...else Statement
[ C# Decision Making](#)
An **if statement** can be followed by an optional **else statement**, which executes when the boolean expression is false.
## Syntax
The syntax of an **if...else** statement in C#:
if(boolean_expression){ /* Executes if the boolean expression is true */}else{ /* Executes if the boolean expression is false */}
If the boolean expression evaluates to **true**, then the code block inside the **if** block is executed. If the boolean expression evaluates to **false**, then the code block inside the **else** block is executed.
## Flowchart
## Example
## Example
using System;
namespace DecisionMaking
{
class Program
{
static void Main(string[] args)
{
/* local variable definition */
int a =100;
/* check the boolean condition */
if(a <20)
{
/* if condition is true then print the following */
Console.WriteLine("a is less than 20");
}
else
{
/* if condition is false then print the following */
Console.WriteLine("a is not less than 20");
}
Console.WriteLine("value of a is: {0}", a);
Console.ReadLine();
}
}
}
When the above code is compiled and executed, it produces the following result:
a is not less than 20 value of a is: 100
## if...else if...else Statement
An **if** statement can be followed by an optional **else if...else** statement, which is useful to test multiple conditions using the if...else if...else ladder.
When using if...else if...else statements, there are a few points to keep in mind:
* An if can have zero or one else's and it must come after any else if's.
* An if can have zero to many else if's and they must come before the else.
* Once an else if succeeds, none of the remaining else if's or else's will be tested.
## Syntax
The syntax of an **if...else if...else** statement in C#:
if(boolean_expression 1){ /* Executes when the boolean expression 1 is true */}else if( boolean_expression 2){ /* Executes when the boolean expression 2 is true */}else if( boolean_expression 3){ /* Executes when the boolean expression 3 is true */}else { /* Executes when the none of the above condition is true */}
## Example
## Example
using System;
namespace DecisionMaking
{
class Program
{
static void Main(string[] args)
{
/* local variable definition */
int a =100;
/* check the boolean condition */
if(a ==10)
{
/* if condition is true then print the following */
Console.WriteLine("Value of a is 10");
}
else if(a ==20)
{
/* if else if condition is true then print the following */
Console.WriteLine("Value of a is 20");
}
else if(a ==30)
{
/* if else if condition is true then print the following */
Console.WriteLine("Value of a is 30");
}
else
{
/* if none of the conditions is true */
Console.WriteLine("None of the values is matching");
}
Console.WriteLine("Exact value of a is: {0}", a);
Console.ReadLine();
}
}
}
When the above code is compiled and executed, it produces the following result:
None of the values is matching Exact value of a is: 100
[ C# Decision Making](#)