冒泡排序-php

<span>PHP实现的代码先奉上：<br>function</span> bubble_sort(<span>$array</span><span>) {
    </span><span>for</span> (<span>$i</span> = 0; <span>$i</span> < <span>count</span>(<span>$array</span>) - 1; <span>$i</span>++) {    <span>//</span><span>$i为已经排过序的元素个数</span>
        <span>for</span> (<span>$j</span> = 0; <span>$j</span> < <span>count</span>(<span>$array</span>) - 1 - <span>$i</span>; <span>$j</span>++) {    <span>//</span><span>$j为需要排序的元素个数,用总长减去$i</span>
            <span>if</span> (<span>$array</span>[<span>$j</span>] > <span>$array</span>[<span>$j</span> + 1]) {    <span>//</span><span>按升序排序</span>
                <span>$temp</span> = <span>$array</span>[<span>$j</span><span>];
                </span><span>$array</span>[<span>$j</span>] = <span>$array</span>[<span>$j</span> + 1<span>];
                </span><span>$array</span>[<span>$j</span> + 1] = <span>$temp</span><span>;
            }
        }
    }
    </span><span>return</span> <span>$array</span><span>;
}<br>$a = array(5, 1, 4, 7);<br>代码执行过程：<br></span>

<span>i = 0;<br>  j = 0;<br>  if($arr[0] > $arr[1]) => 5 > 1 条件成立，交换位置，形成新的数组 =>  1 5 4 7  j++<br>  if($arr[1] > $arr[2]) => 5 > 4 条件成立，交换位置, 形成新的数组 =>  1 4 5 7  j++ <br>  if($arr[2] > $arr[3]) => 5 > 7 条件不成立 ，数组保持不变 ， 1 4 5 7 j++ j=3 退出内层循环， i++</span>

<span>依次类推吧。 <br></span>

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