Question 1:

Write a perl subroutine for temperature conversion named 'convert_temp'. It should be able to handle both Fahrenheit to Celsius conversions as well as Celsius to Fahrenheit conversions. It must accept and read two arguments that are passed to it: first, the temperature scale of the original temperature (only 'F' or 'C' should be used), and second, the number of degrees of the original temperature. It should then convert the original temperature from Fahrenheit to Celsius or from Celsius to Fahrenheit, as appropriate. Finally, this subroutine should print out the original temperature and scale as well as the converted temperature and scale.

Then write a short program to use the subroutine you wrote (both the subroutine and program should be part of the same file). Your program should prompt the user to enter a temperature scale (assume the user will choose to type 'F' or 'C') and then prompt the user to enter a number of degrees. Using the values supplied by the user, the program should then call the 'convert_temp' subroutine and pass in the two arguments, along these lines:

convert_temp($scale, $degrees);

and the subroutine should produce a line of output that looks like this (for Fahrenheit to Celsius):

            98.6 degrees F is 37.0 degrees C or, for a Celsius to Fahrenheit conversion:

            100.0 degrees C is 212.0 degrees F

The first temperature and scale that you should report are those that the user entered, followed by the converted temperature and other scale.

Question 2:

Write a program that prompts the user to enter an oligonucleotide sequence, such as TATGAGCCCGTA. If the user entered a valid oligo sequence consisting only of the characters A, C, G, or T, the program should then display the reverse complement of that sequence, in this case TACGGGCTCATA, along with text indicating that it is the reverse complement.

After displaying the reverse complement, the program should then prompt the user to enter another sequence. The program should continue this pattern of prompting the user for a new oligo sequence and displaying its reverse complement until the user enters a sequence with at least one character that is invalid (i.e. a character other than A, C, G, or T). At this point, the program should end its run with a message that mentions that an invalid character was found, with no further prompting to the user.

Did you know that the reverse() function not only works on arrays, but also in a scalar context where it reverses the letters of a text string? Quite useful! For example:

my $text = "Larry Wall";

reverse($text);    # $text now contains "llaW yrraL"