PHP print Yang Hui triangle small example

Example, php print Yang Hui triangle. /** * Print Yang Hui triangle: * 1 * 1 1 * 1 2 1 * 1 3 3 1 * 1 4 6 4 1 * 1 5 10 10 5 1 * 1 6 15 20 15 6 1 * */ function Yang_hui_san_jiao ($n) { $arr =array (1); $arr record the elements of the previous row $return _html= ' //Outer loop control lines //Inner loop control number of row elements } } } for ($i =1; $i <= $n; $i + +) { $ return_html.= ' for ($j =1; $j <= $i; $j + +) { //The first and last element of a row is always 1 if ($j ==1 | | $j = = $i) { $new _arr[$j]=1 ; Defines a new array $new_arr, records the elements of the current row, $return _html.= ' Else { ///Otherwise, the element is equal to the same angle and angle label on the previous line-12 elements and $new _number= $arr [$j]+ $arr [$j-1]; $new _arr[$j]= $new _number;//assigning elements to a new array $return _html.= ' } $arr = $new _arr;//Assign an array of current rows to $arr and start a new round of loops $return _html.= ' $return _html.= ' ';//define a variable, record the output of HTML '; '; '; '; 1 '. $new _number. ' '; return $return _html; } Call function test Yang Hui triangle Echo Yang_hui_san_jiao (10); ?> Copy Code

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