php class passing value from one function to another

Question

I am trying to learn oop and I'm trying to pass a value from one one function to another inside a class but for some reason it gives me an error of Notice: Trying to get property of non-object, any ideas?

class test{
    function test($value){
    global  $db;
    $stmt = $db->prepare("SELECT * FROM some_table where some_column = ?");
    $stmt->bind_param('s', $value);
    $stmt->execute();
    $res = $stmt->get_result();
    $fetch = $res->fetch_object();
    $this->test = $fetch->some_row;//this is the error line 
}
      function do_something(){
        $name = $this->test;
         return $name;
      }
      }
$p = new test();
$p->test('test');
echo $p->do_something();

It also points you to the exact line where it happens. Since you know a line number and variable - take var_dump() and check the actual variable value. — zerkms
– zerkms, Commented Sep 27, 2014 at 3:27
so - that's why you get an error. You are trying to invoke a method of NULL, which is nonsense. — zerkms
– zerkms, Commented Sep 27, 2014 at 3:49
@zerkms, okay but it turns out that the $value is the prob, if I give it some other value for the bind_param it works. Do you have any idea why the value for function test() not passing? — user2666310
– user2666310, Commented Sep 27, 2014 at 3:59

yogesh suhagiya · Accepted Answer · 2014-09-27 07:24:12Z

1

Try out following code:

<?php

    class test {

        /**
         * @var $test
         **/
        public $test;

        /**
         * Constructor of current class
         **/
        function __construct($value = "") {

            /**
             * Global variable $db must be defined before use at here
             **/
            global  $db;

            $stmt = $db->prepare("SELECT * FROM some_table where some_column = ?");
            $stmt->bind_param('s', $value);
            $stmt->execute();
            $res = $stmt->get_result();
            $fetch = $res->fetch_object();

            $this->test = $fetch->some_row; // Set return value to public member of class
        }

        /**
         * Process and get return value
         **/
        function do_something() {

            $name = $this->test;
            return $name;
        }
    }


    $p = new test('test');
    // $p->test('test'); // You don't need to call this function, because this is the constructor of class 
    echo $p->do_something();

edited Sep 27, 2014 at 7:24

answered Sep 27, 2014 at 5:12

yogesh suhagiya

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1 Comment

TML Over a year ago

Relying on the constructor method being the same name as the class is deprecated - you really should call it __construct.

alagu · Accepted Answer · 2014-09-27 03:49:52Z

0

class Test{

    public function test($value){
        global  $db;
        $stmt = $db->prepare("SELECT * FROM some_table where some_column = ?");
        $stmt->bind_param('s', $value);
        $stmt->execute();
        $res = $stmt->get_result();
        $fetch = $res->fetch_object();
        $var_set = $fetch->some_row;//this is the error line 
        return $var;
    } // end the funtion 

    function do_something($value){
        $name = $this->test($value); // you have to pass an value here 
        return $name;
    }
}

$p = new Test;
$return_value = $p->do_something($value);
print_r($return_value);

answered Sep 27, 2014 at 3:49

alagu

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