#Get the phone number and check to make sure that it contains only digits and the length is 10

while($phone =~ /D/ || $len !=10){
 print "Please enter your 10 digit phone number:";
 $phone = <STDIN>;
 chomp($phone);
 #Find out the length of the string
 $len=($phone=~tr/[0-9]/[0-9]/);
}

#Using regular expressions, break down the phone number into first number the
#next three digits and then the next three digits and so on. Each digits will be
#stored in $1 $2 $3 and $4.

$phone=~/(d)(ddd)(ddd)(ddd)/;
$formattedphone="+".$1." ".$2." ".$3." ".$4;