Question

Use a loop structure and code a program that produces the following output (Take one parameter to let user specify how mans lines need to be printed): AA AAA AAAB AAABA AAABAA AAABAAA AAABAAAB ... Implement a program that processes an input file by changing every occurrence of an old string into a new string. (The usage is: chstr file oldstring newstring, chstr is your program name, file, oldstring and newstring are parameters specified by user.) (Extra Credits) Given an input file, such as text.txt, write a program to perform the following two tasks: it counts the number of words in the file; (Provide definition of your own "words".) it takes one number x as argument, and display the top x most frequency words in the file. List three language features (or design choices) of Perl and evaluate them (state advantages as well as drawbacks) using short paragraphs.

Please answer (1,2,4)having issues

Answer 1

null

Executable Perl Code:

# Number of A in a block
$numA = 3;

# Number of B in a block
$numB = 1;

# Variable for loop
$val_i = 1;

# Output
$out = "";

# Variable for loop
$val_j = 1;

# Number of space to be printed
$spaceAvail=0;

# Loop for number of lines
while ($val_i <= $ARGV[0])
{
   while ($val_j <= $val_i)
   {
       # Whwn new block starts
       if ($numA == 0 && $numB == 0)
       {
          $numA = 3;
          $numB = 1;
       }
       # Output A
       if ($numA > 0)
       {
          $out.= "A";
          $numA--;
       }
       # Output B
       else
       {
          $out.= "B";
          $numB--;
          $spaceAvail++;
       }
       $val_j++;
   }
   # Print output
   print($out . "\n");
  
   # Print required spaces
   for (my $i=0; $i <$spaceAvail; $i++) {
       print(" ");
   }
   $val_i++;
}