PHP Math Exercises: Round a float away from zero to a specified number of decimal places

Last update on December 20 2024 10:19:18 (UTC/GMT +8 hours)

Write a PHP function to round a float away from zero to a specified number of decimal places.

Sample Data :
(78.78001, 2)
(8.131001, 2)
(0.586001, 4)
(-.125481, 3)
-.125481

Sample Solution:

PHP Code:

<?php
function roundout($value, $places = 0) {
    if ($places < 0) { 
        $places = 0; // Ensure places is non-negative
    }
    $x = pow(10, $places); // Calculate the multiplier
    // Round the value based on its sign and the multiplier, then divide by the multiplier
    return ($value >= 0 ? ceil($value * $x) : floor($value * $x)) / $x;
}

// Test the roundout function with different values and precision
echo roundout(78.78001, 2) . "\n";     
echo roundout(8.131001, 2) . "\n";     
echo roundout(0.586001, 4) . "\n";   
echo roundout(-0.125481, 3) . "\n";  
echo roundout(-0.125481);      
?>

Output:

Explanation:

In the exercise above,

'function roundout($value, $places = 0) {': This line defines a function named 'roundout' that takes two parameters: '$value' (the number to be rounded) and '$places' (the number of decimal places to round to, defaulting to 0 if not provided).
'if ($places < 0) { $places = 0; }': This line ensures that the number of decimal places is non-negative. If '$places' is less than 0, it is set to 0.
'$x = pow(10, $places);': This line calculates the multiplier '$x' by raising 10 to the power of the number of decimal places.
'return ($value >= 0 ? ceil($value $x) : floor($value $x)) / $x;': This line rounds the value based on its sign and the multiplier '$x'. If '$value' is non-negative, it is rounded up using 'ceil()'; otherwise, it is rounded down using 'floor()'. The result is then divided by the multiplier to obtain the rounded value.
The subsequent 'echo' statements test the 'roundout' function with different input values and precision levels, and display the rounded results.

Flowchart :

$Flowchart: Round a float away from zero to a specified number of decimal places$

PHP Code Editor:

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