Program control structures

If is a statement that checks the condition and executes the following statements if the condition is true. There are multiple ways how to write down the if statement:

//1st example
if (condition) statement;     
 
//2nd example
if (condition)
statement;                    
 
//3rd example
if (condition) { statement; } 
 
//4th example
if (condition)
{
  statement;
}                             

When both true and false cases of the condition should be viewed, the else part should is added to the if statement in the following ways:

if (condition) {
  statement1;    //executes when the condition is true
}
else {
  statement2;    //executes when the condition is false
}

If more conditions should be viewed, the else if part is added to the if statement:

if (condition1) {
  statement1;    //executes when the condition1 is true
}
else if (condition2) {
  statement2;    //executes when the condition2 is true
}
else {
  statement3;      //executes in all of the rest cases
}

if (x>10) 
{
  digitalWrite(LEDpin, HIGH)  //statement is executed if the x>10 expression is true
}

Logical operators are widely used together with the condition operator if that is described below.

There are multiple comparison operators used for comparing variables and values. Comparison operators are following:

• == (equal to) -
• != (not equal to) -
• < (less than) -
• < = (less than or equal to)
• > (greater than) -
• > = (greater than or equal to) -

The Boolean logical operators

• ! (logical not) -
• && (logical and) -
• || (logical or) -

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