每日一练-20171114

来源：互联网发布：获取php版本号编辑：程序博客网时间：2024/06/06 01:44
一、Java 编程题int a = 10，int b = 20，请实现这两个数的值的交换（变成int a = 20，int b = 10），要求写3种或3种以上的实现方式public class Test {public static void main(String[] args) {int a = 10,b = 20;/*int temp = a;a = b;b = temp;*//*int temp = a + b;a = temp - a;b = temp - a;*/a = a^b;b = a^b;a = a^b;System.out.println("a:"+a);System.out.println("b:"+b);}}二、MySql题请描述MySql从安装到配置的全部详细过程（确保一台新电脑可以顺利使用mysql）1.去官网下载Mysql配置版2.将Mysql注册到系统服务中3.将Mysql的bin目录配置到系统环境变量path中4.通过命令mysql -uroot -p进入数据库三、JS题目请做一个年，月，日的联动菜单<body>  年<select id="year" onchange="change();">  </select>  月<select id="month" onchange="change();">  </select>  日<select id="day">  </select>    <script>    var year = document.getElementById("year");    var month = document.getElementById("month");    var day = document.getElementById("day");    for(var i = 1980;i<=new Date().getFullYear();i++){    var option = document.createElement("option");    option.setAttribute("value",i);    option.innerHTML=i;    year.appendChild(option);    }    for(var i = 1;i<=12;i++){    var option = document.createElement("option");    option.setAttribute("value",i);    option.innerHTML=i;    month.appendChild(option);    }    for(var i = 1;i<=31;i++){    var option = document.createElement("option");    option.setAttribute("value",i);    option.innerHTML=i;    day.appendChild(option);    }    //判断是否是闰年    function isLeapYear(year){    var flag = false;    if((year%4==0&&year%100!=0)||year%400==0){    flag = true;    }    return flag;    }        //判断某年某月对应的天数    function getDay(year,month){    var num = 0;    switch(month){    case "1":    case "3":    case "5":    case "7":    case "8":    case "10":    case "12": num = 31;    break;    case "4":    case "6":    case "9":    case "11": num = 30;    break;    case "2":if(isLeapYear(year)){    num = 29;    }else{    num = 28;    }    break;    }    return num;    }        function change(){    //获取当前年，月    var currYear = year.options[year.selectedIndex].value;    var currMonth = month.options[month.selectedIndex].value;    var days = getDay(currYear,currMonth);    day.innerHTML = "";    for(var i = 1;i<=days;i++){    var option = document.createElement("option");    option.setAttribute("value",i);    option.innerHTML=i;    day.appendChild(option);    }    }    </script>  </body>
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