1 用javascript编写九九乘法表
<!DOCTYPE html> <html> <head> <meta charset="utf-8" /> <title>99乘法表</title> <style type="text/css"> #first { width: 800px;height: 500px; } </style> </head> <body> <div id="first"> </div> <script type="text/javascript"> function chengfa() { var tr = ""; for (var i = 1; i <= 9; i++) { for (var j = 1; j <= i; j++) { tr += i + '*' + j + '=' + i * j + ' '; if (i == j) { tr += "<br>"; } } } document.getElementById('first').innerHTML = tr; } chengfa(); </script> </body> </html>
2 表名 User
DROP TABLE IF EXISTS user; CREATE TABLE `user` ( `name` varchar(255) DEFAULT NULL, `tel` int(255) DEFAULT NULL, `content` varchar(255) DEFAULT NULL, `date` date DEFAULT NULL ) ENGINE=InnoDB DEFAULT CHARSET=utf8; INSERT `user`(name,tel,content,date) VALUES('tom',1111,'大专毕业','2006-10-11'); INSERT `user`(name,tel,content,date) VALUES('jack',1111,'本科毕业','2006-10-15'); INSERT `user`(name,tel,content,date) VALUES('tonny',1111,'中专毕业','2006-10-18'); -- 1、有一新记录(heby 2222 中专毕业2006-10-20),请用SQL语句新增至表中。 INSERT `user`(name,tel,content,date) VALUES('heby',2222,'中专毕业','2006-10-20'); -- 2、请用 SQL 语句,把tom的时间更新为当前系统时间。 UPDATE `user` SET DATE = NOW() WHERE name = 'tom'; -- 3、请写出删除姓名为heby的全部记录。 DELETE FROM `user` WHERE name = 'heby';
3 有 1、2、3、4 个数字,能组成多少个互不相同且无重复数字的三位数?都是多少?
package Demo; public class Test { public static void main(String[] args) { String str = ""; //遍历百位 for (int i = 1; i <= 4; i++) { //遍历十位 for (int j = 1; j <= 4; j++) { //若和百位相同,则跳出循环 if (j == i) { continue; } //遍历个位 for (int k = 1; k <= 4; k++) { //若和百位或者十位相同,则跳出循环 if (k == j || k == i) { continue; } str += (i * 100 + j * 10 + k + ","); } } } /*public String substring(int beginIndex, int endIndex) { if (beginIndex < 0) { throw new StringIndexOutOfBoundsException(beginIndex); } if (endIndex > value.length) { throw new StringIndexOutOfBoundsException(endIndex); } int subLen = endIndex - beginIndex; if (subLen < 0) { throw new StringIndexOutOfBoundsException(subLen); } return ((beginIndex == 0) && (endIndex == value.length)) ? this : new String(value, beginIndex, subLen); }*/ System.out.print(str.substring(0, str.length() - 1)); } }