javascript打印杨辉三角图 

打印杨辉三角图
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>杨辉三角</title>
    <style type="text/css">
        html,body{
            padding: 0;margin: 0; width: 100%; height: 100%;
        }
        #res{
            padding: 5px 20px;;
        }
        span{
            padding-right: 5px; display: inline-block; width: 35px;
        }
    </style>
</head>
<body>
<h1>打印杨辉三角图。</h1>

<div id="res">
<h2>结果:</h2>
</div>
<script type="text/javascript">
    (function(window,document){/***
         * 1
         * 1 1
         * 1 2 1
         * 1 3 3 1
         * 1 4 6 4 1
         * ......
         * 打印rowNum行的杨辉三角
         */
        function getRes(rowNum){
            var arr=[];
            for(var r=1;r<=rowNum;r++) {
                arr[r]=[0];
                var div=document.createElement("div");
                for(var c=1;c<=r;c++){
                    var data;
                    if(c===1){
                        data=1;
                    }else{
                        var a=arr[r-1][c-1]||0,b=arr[r-1][c]||0;
                        data=a+b;
                    }
                    arr[r].push(data);
                    var span=document.createElement("span");
                    var text=document.createTextNode(data);
                    span.appendChild(text);
                    div.appendChild(span);
                }
                document.getElementById("res").appendChild(div);
            }
            console.log(arr);
        }
        getRes(10);
    })(window,document)
</script>
</body>
</html>

 

posted @ 2017-03-03 16:42  甘小春  Views(533)  Comments(0)    收藏  举报