A PHP Error was encountered

Severity: Notice

Message: Undefined offset: -1

Filename: frontend/C_f_frontend.php

Line Number: 55

Backtrace:

File: /home/agp22a22/domains/xaydungangiaphu.com/public_html/application/controllers/frontend/C_f_frontend.php
Line: 55
Function: _error_handler

File: /home/agp22a22/domains/xaydungangiaphu.com/public_html/index.php
Line: 315
Function: require_once