maybe something like this:

use strict;
use warnings;

{
my $template = <<'EOF';
string tymchasovyi(%PROMPT%);
int %VARIABLE% = read(tymchasovyi);
EOF
sub populate_template
{
    my($v,$p) = @_;
    my $t = $template;
    $t =~ s/%VARIABLE%/$v/g;
    $t =~ s/%PROMPT%/$p/g;
    $t
}
}

for ( @lines )
{
    s(\bint\s+(\w+)\s*=\s*read\s*\((.*)\)\s*;){ populate_template($1,$
+2) }e;
}
[download]

but caveat that if you have more than one of those in the same scope, you'll get 'redefined variable' warnings.