PHP Exercises: Test if circumference of two circles intersect or overlap

Last update on May 30 2022 11:43:50 (UTC/GMT +8 hours)

PHP: Exercise-58 with Solution

There are two circles C1 with radius r1, central coordinate (x1, y1) and C2 with radius r2 and central coordinate (x2, y2)
Write a PHP program to test the followings -
"C2 is in C1" if C2 is in C1
"C1 is in C2" if C1 is in C2
"Circumference of C1 and C2 intersect" if circumference of C1 and C2 intersect, and and "C1 and C2 do not overlap" if C1 and C2 do not overlap.

Input:Input numbers (real numbers) are separated by a space.
Input 0 to exit.

Sample Solution: -

PHP Code:

<?php
$n = intval(fgets(STDIN));
for($i = 0; $i < $n; $i++){
    fscanf(STDIN, "%lf %lf %lf %lf %lf %lf", $xa, $ya, $ra, $xb, $yb, $rb);
     
    $r = sqrt(($xb - $xa)*($xb - $xa) + ($yb - $ya)*($yb - $ya));
    if($r + $ra < $rb){
        echo "C1  is in C2\n";
        continue;
    }
    if($r + $rb < $ra){
        echo "C2  is in C1.\n";
        continue;
    }
     
    if($r <= $ra + $rb){
        echo "Circumference of C1  and C2  intersect.";
        continue;
    }
    echo "C1 and C2 do not overlap.\n";
}
?>

Sample Input:
2
0.0 0.0 6.0 0.0 0.0 5.0
0.0 0.0 3.0 5.1 0.0 3.0

Sample Output:

C2  is in C1.
Circumference of C1  and C2  intersect.

Flowchart:

PHP Code Editor:

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Previous: Write a PHP program to find the maximum sum of a contiguous subsequence from a given sequence of numbers a1, a2, a3, ... an. A subsequence of one element is also a continuous subsequence.
Next: Write a PHP program to that reads a date (from 2004/1/1 to 2004/12/31) and prints the day of the date. Jan. 1, 2004, is Friday. Note that 2004 is a leap year.

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PHP: Tips of the Day

How to Sort Multi-dimensional Array by Value?

Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

Example:

function sortByOrder($a, $b) {
    return $a['order'] - $b['order'];
}

usort($myArray, 'sortByOrder');

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {
    return $a['order'] - $b['order'];
});

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) {
    return $a['order'] <=> $b['order'];
});

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) {
    $retval = $a['order'] <=> $b['order'];
    if ($retval == 0) {
        $retval = $a['suborder'] <=> $b['suborder'];
        if ($retval == 0) {
            $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder'];
        }
    }
    return $retval;
});

If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual

Ref : https://bit.ly/3i77vCC