#/usr/bin/perl -w
use strict;
my $data;
while(<DATA>) {
 last if ($_ eq "");
 $data .= $_;
}

print $data;
if ( $data =~ /if.*?\{/s ) { # New RegEx
 $data =~ s/\{//;
 $data =~ s/\}//;
}

print $data;
__DATA__
if (c=e)
     {    //delete these curly braces               
      call pgme;
      call pgmd;
      }                //delete these curly braces
     else
       {call pgmd;     // keep these curly braces
        call pgmc;}

##</code><code>##

Output:
if (c=e)
                //delete these curly braces                   
      call pgme;
      call pgmd;
                      //delete these curly braces
     else
       {call pgmd;     // keep these curly braces
        call pgmc;}