一，登录页面流程图
二，功能流程图
三，页面登陆代码及效果展示；
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<html>
<head>
<title> 简单的用户登录表单实现 </title>
<style type="text/css">
a{color: #000000;font-size: 24px;}
fieldset
{
margin:20px auto;
width:600px;
height:200px;
padding:20px auto;
color:#000000;
text-align:center;
}
legend
{
color:#000000;
font-size:24px;
font-weight:bold;
text-align:center;
}
</style>
<script type="text/javascript">
function checklogin()
{
var username=document.getElementById("myname").value;
var pwd=document.getElementById("mypwd").value;
if(username=="")
{
alert("用户名不能为空！！");
document.getElementById("myname").focus();
return false;
}
else
{
if(username.length<8||username.length>20)
{
alert("用户名太短，应在8~20个字符之间！！");
document.getElementById("myname").focus();
return false;
}
}
if (pwd=="")
{
alert("密码不能为空！！");
document.getElementById("mypwd").focus();
return false;
}
else
{
if(pwd.length<8||pwd.length>20)
{
alert("密码太短，应在6~20个字符之间！！");
document.getElementById("mypwd").focus();
return false;
}
}
return true;
}
</script>
</head>
<body>
<form name="loginform" method="post" action="loginindex.html" onsubmit="return checklogin()">
<fieldset>
<legend align="center">用户登录</legend>
<br><br>
<label>用户名</label>
<input type="text" name="" id="myname" ><br><br>
<label>密 码</label>
<input type="password" name="" id="mypwd" ><br><br><br>
<input type="submit" value="提交">
<input type="reset">
</fieldset>
</form>
</body>
</html>
四，计算器设计
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Calculator {
private JFrame frame;
private JTextField textField;
private JButton btn1, btn2, btn3, btn4, btn5, btn6, btn7, btn8, btn9, btn0;
private JButton btnAdd, btnSubtract, btnMultiply, btnDivide, btnEquals, btnClear;
private double firstNumber;
private String operator;
public Calculator() {
frame = new JFrame("Calculator");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 400);
frame.setLayout(new BorderLayout());
textField = new JTextField();
textField.setHorizontalAlignment(JTextField.RIGHT);
JPanel panel = new JPanel();
panel.setLayout(new GridLayout(4, 4));
btn1 = new JButton("1");
btn2 = new JButton("2");
btn3 = new JButton("3");
btn4 = new JButton("4");
btn5 = new JButton("5");
btn6 = new JButton("6");
btn7 = new JButton("7");
btn8 = new JButton("8");
btn9 = new JButton("9");
btn0 = new JButton("0");
btnAdd = new JButton("+");
btnSubtract = new JButton("-");
btnMultiply = new JButton("*");
btnDivide = new JButton("/");
btnEquals = new JButton("=");
btnClear = new JButton("C");
panel.add(btn1);
panel.add(btn2);
panel.add(btn3);
panel.add(btnAdd);
panel.add(btn4);
panel.add(btn5);
panel.add(btn6);
panel.add(btnSubtract);
panel.add(btn7);
panel.add(btn8);
panel.add(btn9);
panel.add(btnMultiply);
panel.add(btn0);
panel.add(btnClear);
panel.add(btnEquals);
panel.add(btnDivide);
frame.add(textField, BorderLayout.NORTH);
frame.add(panel, BorderLayout.CENTER);
frame.setVisible(true);
btn1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
textField.setText(textField.getText() + "1");
}
});
btn2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
textField.setText(textField.getText() + "2");
}
});
// 添加其他按钮的监听器
btnAdd.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
firstNumber = Double.parseDouble(textField.getText());
operator = "+";
textField.setText("");
}
});
btnEquals.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
double secondNumber = Double.parseDouble(textField.getText());
double result = 0;
if (operator.equals("+")) {
result = firstNumber + secondNumber;
} else if (operator.equals("-")) {
result = firstNumber - secondNumber;
} else if (operator.equals("*")) {
result = firstNumber * secondNumber;
} else if (operator.equals("/")) {
result = firstNumber / secondNumber;
}
textField.setText(String.valueOf(result));
}
});
btnClear.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
textField.setText("");
}
});
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new Calculator();
}
});
}
}
我们使用的算法思想是牛顿迭代法Q Qpackage package1 ;
import java.util .Scanner ;
public class t010fx {
public static void main(String args[])Scanner S = new Scanner (System. in);
System . out . pr intln("请输入一个你想开方的值int C = s.nextInt( );
double x1 ,X0 = C;
double fx = 2*x0;
x1 = x0 - (x0*x0-c)/fx;
while(Math.abs(x1-x0)>1e-16){
x0 = x1;
x1 = x0 - (x0*x0-c)/fx;
}
System. out.println(C+"开方的结果是"+X1);}
此时的运算结果如下:
六，数据库连接
<?php
class Mysql{
private $host;
private $root;
private $passwords;
private $database;
#析构函数，具有构造函数的类，在创建对象时会调用构造函数，完成一些初始化的操作。
function __construct($host,$root,$passwords,$database){
$this->host = $host; # $this-> 在类本身内部使用本类的属性或者方法
$this->root = $root;
$this->passwords = $passwords;
$this->database = $database;
$this->connect();
}
#连接数据库
function connect(){
$this->conn=mysqli_connect($this->host,$this->root,$this->passwords); #连接数据库服务器
mysqli_query($this->conn,"set names utf8"); #设置字符集
mysqli_select_db($this->conn,$this->database); #选择数据库
}
#创建查询结果集
function query($sql){
return mysqli_query($this->conn,$sql);
}
#返回结果集中的记录总数
function rows($result){
return mysqli_num_rows($result);
}
#自定义查询方法selectbyId
function selectbyUser($table,$username){
return $this->query("SELECT * FROM $table where username='$username'");
}
//自定义插入数据方法
function insert($table,$username,$password){
$this->query("INSERT INTO $table (username,password) VALUES ('$username','$password')");
}
#mysql_fetch_assoc() 函数从结果集中取得一行作为关联数组。
function assoc($result){
return mysqli_fetch_assoc($result);
}
#数据库关闭
function dbClose(){
mysqli_close($this->conn);
}
}
$db = new Mysql("localhost","root","123456","test");
?>