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

PHP math: Exercise-8 with Solution

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:

78.79                                                       
8.14                                                        
0.5861                                                      
-0.126                                                      
-1 

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 :

PHP Code Editor:

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