将十进制值四舍五入为精确的整数值php

Question

I have came across the php rounding decimal values by using:
The round() function rounds a floating-point number.
To round a number UP to the nearest integer, look at the ceil() function.
To round a number DOWN to the nearest integer, look at the floor() function.

I have an example of dividing 1000/13 which when we use
round(1000/13, 2) will give you 999.98 and then i will use ceil to round it to 1000.
Now, my value is 925.6 which has to be divided by 11 and I tried with the
round(925.6/11, 2) which will give 84.15, then if u multiply this with 11(84.15 * 11)then you will get 925.56 . Now how can achieve the exact decimal if any decimal input.

Answer 1

Rounding-off a Double or Float using round() , ceil() or floor() all have one thing in Common and that is: by using them you are subscribing to losing the Precision of your Data. This means; once the die is cast, you cannot get the Original value again.... it is that simple:

If you want to retain both the Truncated and the Original Values, you have to do it differently.... You may need to keep 2 Variables or simply put your Variables in an Array. A Simple example would demonstrate this even better:

<?php

        $num        = (925.6/11);

        // STORE THE ORIGINAL & ROUNDED VALUES IN AN ARRAY (IN CASE YOU NEED BOTH)
        $arrNumbers = [
                'original'  =>  $num,
                'rounded'   =>  round($num, 2),
        ];

        // NOW; FOR YOUR MULTIPLICATIONS:
        $original   = $arrNumbers['original'] * 11;
        $broken     = $arrNumbers['rounded']  * 11;


        var_dump($original);    //<== float 925.6
        var_dump($broken);      //<== float 925.65    :: ADDED AN EXTRA 0.05 (BOGUS, HUH?)
        var_dump($arrNumbers);  //<== array (size=2) 'original' => float 84.1454545455  'rounded' => float 84.15

UPDATE: NUMERATOR AS A VALUE FROM FORM-FIELD.

     <?php

        // ASSUME THE VALUE OF THE NUMERATOR IS: 925.6
        $numerator      = htmlspecialchars(trim($_POST['some_field'])); 

        // AND THE DENOMINATOR IS NOW SOMETHING LIKE MONTH 11 AS IN: 11.0000
        $denominator    = 11.0000;                                           

        // NO PROBLEMS STILL...
        $num            = ($numerator/$denominator);

        // STORE THE ORIGINAL & ROUNDED VALUES IN AN ARRAY (IN CASE YOU NEED BOTH)
        $arrNumbers     = [
                'original'  =>  $num,
                'rounded'   =>  round($num, 2),
        ];

        // NOW; FOR YOUR MULTIPLICATION,
        // TO GET THE STARTING VALUES BACK DO:
        $original       = $arrNumbers['original'] * 11;
        $broken         = $arrNumbers['rounded']  * 11;


        var_dump($original);    //<== float 925.6
        var_dump($broken);      //<== float 925.65    :: ADDED AN EXTRA 0.05 (BOGUS, HUH?)
        var_dump($arrNumbers);  //<== array (size=2) 'original' => float 84.1454545455  'rounded' => float 84.15