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  • JS循环、数组与练习题

    <!DOCTYPE html>
    <html>
        <head>
            <meta charset="UTF-8">
            <title></title>
        </head>
        <body>
        </body>
    </html>
    <script type="text/javascript">
        //循环语句:满足判断条件继续执行循环,不满足判断条件停止执行。
        //1.while循环:先判断条件,再执行循环
        /*var one = 0;
        var two = 0;
        while(one <= 20){
            two = two + one;
            one++;
        }
        alert(two);*/
        //2.do-while循环:循环体内的代码,至少执行一次
        /*var one = 0;
        var two = 0;
        do{
            two = two + one;
            one++;
        }while (two < 30);
        alert(one);*/
        //for循环
        /*var two = 0;
        for(var one = 0; one <= 20; one++){
            two = two + one;    
        }
        alert(two);*/
            //跳转语句
                //1.continue(跳过)
                for(var i = 1; i <= 10;i++){
                    if(i == 6){
                        continue;
                    }
                    alert(i);
                }
                //2.break(结束)
                    for(var i = 1;i <= 10;i++){
                        if(i == 6){
                        break;}
                        alert(i);
                    }        
      //数组            
            //定义方式
                //空数组的定义方式
                    var attr = new Array();
                    var attr = [];
                    var attr =new Array(3);
                //有值的数组定义
                     var attr = new Array("zhangsan","lisi","wangwu");
                    var attr2 = ["zhangsan","lisi","wangwu"];
                    alert(attr2.length);
                //数组的遍历
                    //1.for遍历
                     for(var i = 0;i < attr2.length;i++){
                        alert(attr2[i]);
                    }
                    //2. console.log(attr2);
                    var attr2 = ["zhangsan","lisi","wangwu"];
                        0: "zhangsan"
                        1:"sili"
                        2:'wangwu'
                        length:3
                    //3. for-in 遍历
                    for(var k in attr2){
                        alert(attr2[k]);
                    }
                //数组的赋值:
                    //定义一个空数组,对它进行赋值
                    var aa = new Array();
                    aa[0] = "茄子";
                    aa[1] = "西红柿";
                    aa[2] = "菜椒";
                    aa[3] = "黄瓜";
                    console.log(aa); 
                   //循环赋值
                    for(var i = 0; i <= 5;i++){
                         attr[i] = i + 1;
                     }
                     attr = [1,2,3,4,5,6];
                     console.log(attr);
                    
    /*小练习题1:1-n求和练习题 var two = 0; for(var one = parseInt(prompt("请输入一个数值"));one >= 1;one --){ two = two + one; } alert(two);*/ //2.输入台阶数,求总得分: /*var jieShu = parseInt(prompt("请输入您所在的阶数")); var fen = 0; if(jieShu <= 49){ for(var n = jieShu;n >=1;n-- ){ fen = fen + n; } }else if(jieShu > 49 && jieShu <= 100){ fen = (jieShu - 49) * 10 + 1225; }else{ fen = "输入错误,请输入一到一百的整数" } alert(fen);*/ //3:一张纸厚0.0001米,喜马拉雅山高8848米,叠多少次可以达到? /*var ci = 0; for(var zhi = 0.0001;zhi < 8848; zhi *= 2){ ci++; } alert(ci + "次");*/ //一张纸厚0.0001米,喜马拉雅山高8848米,叠多少次可以达到? /*var gao = 0.0001; var i = 0; while(gao < 8848){ i++; gao = gao * 2 } alert(i);*/ //4.篮球练习题:篮球从100米高度落下,每次重新弹起高度是原先的0.6,落到一米需要多少次? /*var ci = 0; for(var zhi = 100;zhi > 1; zhi *= 0.6){ ci++; } alert(ci + "次");*/ //5.列出100内的所有偶数 /*for(var one = 0; one <= 100 ;one++){ if(one % 2 == 0){ two = one; document.write(two + "<br />"); } }*/ /*6.九九乘法表 for(var x = 1;x <= 9;x++){ for(var y = 1;y <= x;y++){ document.write( x + "*" + y + "=" + x * y+"&nbsp;&nbsp;"); } document.write("<br />"); }*/ /*7.100以内与7相关的数 var str =""; for(var yi = 1; yi <= 100;yi ++){ if(yi % 7 == 0){ str += yi+","; }else if((yi - 7) % 10 == 0 ){ str += yi+","; } else if(yi > 70 && yi < 80){ str += yi+","; } } document.write(str);*/ //8.求100以内的质数 /*for(var n = 2;n <= 100;n++){ var m = 1; for(var x = 2; x < n;x++){ if(n % x == 0){ m = 0; } } if(m == 1){ console.log(n); } }*/ //9.购物卡问题:有一百元购物卡,牙刷单价5元,香皂单价2元;洗发水单价15元,有多少种方法可以把一百元刚好用完? /*var n = 0; for(var y = 0;y <= 20;y++){ for(var x = 0;x <=50;x++){ for(var s = 0; s <= 6;s++){ if((5 * y + 2 * x + 15 * s) == 100){ document.write("牙刷:" + y + "支," + "香皂:" + x + "块," + "洗发水" + s + "瓶," + "<br />") n++; } } } } console.log(n);*/ </script>

    练习题1:

    练习题2:

    练习题3:

    练习题4:

    练习题5:

    练习题6:

    练习题7:

    练习题8:

    练习题9:

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  • 原文地址:https://www.cnblogs.com/0328dongbin/p/8761613.html
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