Design a program to produce a number pyramid. That is, given a starting digit from 1 to 9 produce a pyramid containing that number of lines, beginning with a 1 and continuing, on each successive line, with an ascending - descending sequence from 1 to the number and back again.
<? // generate a random number of lines to create $lines = mt_rand(1, 9); // store numbers for use later $numbers = '123456789'; // show fixed width echo '<pre>' . $lines . ':<br/>'; // loop through each line for ($n = 1; $n <= $lines; $n++) { // create spaces to form the pyramid effect $spaces = str_repeat(' ', $lines-$n); // show the numbers ascending and then descending $line = substr($numbers, 0, $n) . strrev(substr($numbers, 0, $n-1)); // output this line of the pyramid echo $spaces . $line . '<br/>'; } // return to normal widths echo '</pre>';?>Which produces:
9:
1
121
12321
1234321
123454321
12345654321
1234567654321
123456787654321
12345678987654321