Calculate the area of a rectangular

Write a program that computes the area of a rectangular.

• Start by having two hard coded values. Multiply them and print the result. The result should be 42:

$ perl example.pl
42

• Then change the code to prompt the user for two numbers. Multiply them and print the result:

$ perl example.pl
First number: 7
Second number: 6
42

# ruby example.rb
First number: 3
Second number: 11
33

• Further modify the program to warn if one of the numbers given was negative.

$ python example.py
First number: 3
Second number: -1
Warning: Invalid input. The side of a rectangular cannot be negative.