Arduino if-else and else-if

The else and else-if both are used after specifying the if statement. It allows multiple conditions to be grouped.

If else

The if-else condition includes if ( ) statement and else ( ) statement. The condition in the else statement is executed if the result of the If ( ) statement is false.

The flowchart is shown below:

Let's understand with an example.

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

The else( ) statement can also include other if statements. Due to this, we can run multiple statements in a single program.

The flowchart is shown below:

The statements will be executed one by one until the true statement is found. When the true statement is found, it will skip all other if and else statements in the code and runs the associated blocks of code.

Code Example

Let's understand if else statement with the help of two examples.

Example 1:

Consider the below code.

int a = 5;
int b= 6;
void setup ( )
{
Serial.begin ( 9600 );
}
void loop ( )
{ 
if ( a > b )
{
Serial.println ( " a is greater " );
}
else
{
Serial.println ( " a is smaller " );
}
}

In the above example, the values are initialized to the variables a and b. The message concerning the satisfied condition will be printed.

Example 2:

Consider the below code.

const int LED1 = 4;
int x = 150 ;
void setup ( )
{ 
Serial.begin( 9600 );
pinMode ( LED1, OUTPUT);
}
void loop ( )
{ 
if ( x > 100 )
{
digitalWrite(LED1, HIGH);
Serial.println ( " LED1 will light +++");
delay (500);
}
else
{
Serial.println ( "LED1 will not light"); 
}
}

Output: LED1 will light +++

If the initialized value of x is less than 100, the message ' LED1 will not light ' will be printed in the output.

Else if

The else if statement can be used with or without the else ( ) statement. We can include multiple else if statements in a program.

Let's understand with an example.

if (condition)
{
// statements
}
else if ( condition)
{
// statements
// only if the first condition is false and the second is true
}
else
{
//statements
}

Code Example

Let's understand else-if statement with the help of an example.

Example 1:

Consider the below code.

int i = 2;
int j = 3;
void setup ( )
{
  Serial.begin(9600);
}
void loop ( )
{
  if ( i > j )
  {
    Serial.println( " I is greater ");
  }
  else if ( i < j )
  {
    Serial.println( " J is greater " );
  }
  else
  {
    Serial.println( " Both are equal " );
  }
}

Output: J is greater

The else if ( ) statement will stop the flow once its execution is true.