# Scalars are simple variables that hold one value
$myNum = 100;                  # Number
$decimal = -5.742;             # Floating point number
$sampleText = "Hello World!";  # String

# Scalars can be references, which hold the location of data
$myRef = \$sampleText;  # myRef holds the location of sampleText

# Dereference (get value at reference's location)
print ${$myRef};  # The first $ may change based on data type

@scores = (95, 86, 92);
@subjects = ("Math", "History", "Writing");

$myNum = $scores[0];
$faveSubject = $subjects[2];
              

# Hashes are key/value pairs

%ages;  # declare an empty hash
$ages{'Bob'} = 35;  # 35 is the value for the key 'Bob'
$ages{'Jane'} = 20;

$ageOfJane = $ages{'Jane'};  # Gets value 20 from the hash
              

# This line is a comment
# Use the pound sign to start your comments

$myNum = 0;
$myNum = $myNum + 1;

#   + : Addition            - : Subtraction
#   * : Multiplication      / : Division
#   % : Modulus Division    **: Exponent

if ($myNum == 0) {
   $myNum = $myNum + 1;
}

#   == : Equal to                  != : Not Equal to
#   >  : Greater than              <  : Less than
#   >= : Greater than or equal to  <= : Less than or equal to

if ($myNum > 1) {
   $result = "myNum is greater than 1";
} elsif ($myNum < 1) {
   $result = "myNum is less than 1";
} else {
   $result = "myNum is equal to 1";
}

# While Loop
while ($myNum < 50) {
   $myNum = $myNum + 1;
}

# For Loop
# initial value; condition; increment
for ( $i = 0; $i < 10; $i++ ) {
   $myNum = $myNum + 1;
}

# Subroutines are very similar to functions from other languages

sub addValues {
   my ($val1, $val2) = @_;  # @_ is the array of arguments
   return $val1 + $val2;
}

$sum = addValues(15, 42);