open (IN, 'file.txt');
open (OUT, '>output.txt');
while (<IN>) {
    print OUT $_;
    if (/^printf\("hello boddy...."\);\s*$/) {
        print OUT qq{char *point = new char[10];\n};
        print OUT qq{printf("complete..\n");\n};
    }
}
close OUT;
close IN;

##</code><code>##

#!/usr/bin/perl -i -p
# perl foo.pl file.txt
if (/^printf\("hello boddy...."\);\s*$/) {
    $_ .= qq{char *point = new char[10];\n}
       .  qq{printf("complete..\n");\n};
}