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The first tool that you need to begin to use control structures is the ability to write code "blocks". A block of code could be any of the code examples that we have seen thus far. The only difference is, to make them a block, we would surround them with {}.

     use strict;
     my $var;

Anything that looks like that is a block. Blocks are very simple, and are much like code blocks in languages like C, C++, and Java. However, in Perl, code blocks are decoupled from any particular control structure. The above code example is a valid piece of Perl code that can appear just about anywhere in a Perl program. Of course, it is only particularly useful for those functions and structures that use blocks.

Note that any variable declared in the block (in the example, $var) lives only until the end of that block. With variables declared my, normal lexical scoping that you are familiar with in C, C++, or Java applies.