CodeIgniter BMI calculator not working

Question

I have been using Codeigniter for an assignment in university and I cannot seem to get this to work, any feedback and fixes are greatly appreciated. The errors returned are:

Undefined index: submit
Undefined variable: weight
Undefined variable: height
Division by zero

This is the code that doesnt work, it is a file in the views folder:

<div id="container">
<h1>BMI and Blood Pressure Calculator</h1>

<div id="body">
    <p>This webpage allows users to calculate their BMI and Blood Pressure by entering in their values into the boxes</p>
    </br>           
    <p>Please enter in your details below</p>

<form>
     <br />
     <br />Patient Information
     <br />Height <input type="text" name="height" size="12" maxlength="20">
     <br />Weight <input type="text" name="weight" size="12" maxlength="20">
     <br />
     <br /><input type="reset" value="Clear Form">
     <br /><input type="submit" value="Submit Information">
</form>
</div>

<?php

        $this->input->post('height');
        $this->input->post('weight');

          if ($_GET['submit']) {
          $height = $_GET['height'];
          $weight = $_GET['weight'];
        }
          function bmi($height,$weight) {
            $bmi = $weight/($height*$height);
            return $bmi;
        }

            $bmi = bmi($weight,$height);

              if ($bmi <= 15) {
                $output = "Very severely underweight";

              } else if ($bmi > 15 AND $bmi<=16 ) {
                $output = "Severely underweight";

              } else if ($bmi > 16 AND $bmi<=18.5) {
                $output = "Underweight";

              } else if ($bmi > 18.5 AND $bmi<=25) {
                $output = "Normal";

              } else if ($bmi > 25 AND $bmi<=30) {
                $output = "Overweight";

              } else if ($bmi > 30 AND $bmi<=35) {
                $output = "Obesity class 1";

              } else if ($bmi > 35 AND $num<=40) {
                $output = "Obesity class 2";

              } else if ($bmi > 60) {
                $output = "Obesity class 3";

              echo "Your BMI is " . $bmi . " and you are : ";
              echo "$output";

              }
        ?>

You are trying to post and get data from where? How do you send this data? Attach also the file that you are handling the inputs — pr1nc3, May 11 '18 at 14:20
Im inputting data via a form and trying to use that data to calculate the inputted data — user9776860, May 11 '18 at 14:24
Yes but how do you send your data? Also your form is not included in your file. Attach also the html please — pr1nc3, May 11 '18 at 14:24
it's better to use `isset` or `!empty` when checking for GET/POST/REQUEST variables. — aynber, May 11 '18 at 14:28
All i really need is a way to declare the variables and fix the division problem, thank you for your replies — user9776860, May 11 '18 at 14:38

score 0 · Answer 1 · answered May 11 '18 at 14:37

I don't think your view page gets to access $this->input directly unless you pass it from the controller to the view. The ideal way to do this would be

on submit of the form receive the values in the controller [ you will need to post to localhost/project_folder/Calc ]

<?php defined('BASEPATH') OR exit('No direct script access allowed');

class Calc extends CI_Controller
{
    public function __construct()
    {
        parent::__construct();
    }

    public function index()
    {
        $data['height'] = $this->input->post('height', true);
        $data['weight'] = $this->input->post('weight', true);
        $this->load->view('page_which_contains_your_logic',$data);
    }
}

Then on the page you can do the following

echo $height." ".$weight;

You should have a better look at the codeigniter documentation to see how data flows between the model, view and controllers.

CodeIgniter BMI calculator not working

1 Answers1