How exceptions can be handled?

The try-catch is the simplest method of handling exceptions. Put the code you want to run in the try block, and any Java exceptions that the code throws are caught by one or more catch blocks. This method will catch any type of Java exceptions that get thrown. This is the simplest mechanism for handling exceptions.

What is $@ in Perl?

2. $@ The Perl syntax error or routine error message from the last eval, do-FILE, or require command. If set, either the compilation failed, or the die function was executed within the code of the eval.

What is undef in Perl?

undef is used for those variables which do not have any assigned value. So basically when the programmer will declare a scalar variable and don’t assign a value to it then variable is supposed to be contain undef value. In Perl, if the initial value of a variable is undef then it will print nothing.

What is the meaning of $_ in Perl?

The most commonly used special variable is $_, which contains the default input and pattern-searching string. For example, in the following lines − #!/usr/bin/perl foreach (‘hickory’,’dickory’,’doc’) { print $_; print “\n”; }

How do I use undef in Perl?

Perl

1. Output:
2. undef() function: undef is used to reset the value of any variable.
3. defined() function: This function is used to check whether a value is assigned to the variable or not.
4. Note: Although undefined variables have no defined value, but they can take null value during the operation.

How do you check if a variable is uninitialized in Perl?

Perl doesn’t offer a way to check whether or not a variable has been initialized. However, scalar variables that haven’t been explicitly initialized with some value happen to have the value of undef by default. You are right about defined being the right way to check whether or not a variable has a value of undef .

Why $_ is used in Perl?

There are some variables which have a predefined and special meaning in Perl. They are the variables that use punctuation characters after the usual variable indicator ($, @, or \%), such as $_ ( explained below )….Global Scalar Special Variables.